DataGridColumnStyle Classe

Definizione

public ref class DataGridColumnStyle abstract : System::ComponentModel::Component, System::Windows::Forms::IDataGridColumnStyleEditingNotificationService

public abstract class DataGridColumnStyle : System.ComponentModel.Component, System.Windows.Forms.IDataGridColumnStyleEditingNotificationService

type DataGridColumnStyle = class
    inherit Component
    interface IDataGridColumnStyleEditingNotificationService

Public MustInherit Class DataGridColumnStyle
Inherits Component
Implements IDataGridColumnStyleEditingNotificationService

Ereditarietà

Object

MarshalByRefObject

Component

DataGridColumnStyle

Derivato

System.Windows.Forms.DataGridBoolColumn

System.Windows.Forms.DataGridTextBoxColumn

Implementazioni

IDataGridColumnStyleEditingNotificationService

Esempio

Nell'esempio di codice seguente viene creato un oggetto DataGridColumnStyle che ospita un DateTimePicker controllo.

#using <System.dll>
#using <System.Data.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
#using <System.Xml.dll>

using namespace System;
using namespace System::Data;
using namespace System::Windows::Forms;
using namespace System::Drawing;
using namespace System::Security::Permissions;

// This example shows how to create your own column style that
// hosts a control, in this case, a DateTimePicker.

public ref class CustomDateTimePicker : public DateTimePicker
{
protected:
    [SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
    virtual bool ProcessKeyMessage( Message% m ) override
    {
        // Keep all the keys for the DateTimePicker.
        return ProcessKeyEventArgs( m );
    }
};

public ref class DataGridTimePickerColumn : public DataGridColumnStyle
{
private:
   CustomDateTimePicker^ customDateTimePicker1;

   // The isEditing field tracks whether or not the user is
   // editing data with the hosted control.
   bool isEditing;

public:
   DataGridTimePickerColumn()
   {
      customDateTimePicker1 = gcnew CustomDateTimePicker;
      customDateTimePicker1->Visible = false;
   }

protected:
   virtual void Abort( int /*rowNum*/ ) override
   {
      isEditing = false;
      customDateTimePicker1->ValueChanged -=
         gcnew EventHandler( this, &DataGridTimePickerColumn::TimePickerValueChanged );
      Invalidate();
   }

   virtual bool Commit( CurrencyManager^ dataSource, int rowNum ) override
   {
      customDateTimePicker1->Bounds = Rectangle::Empty;

      customDateTimePicker1->ValueChanged -=
         gcnew EventHandler( this, &DataGridTimePickerColumn::TimePickerValueChanged );
      
      if (  !isEditing )
         return true;

      isEditing = false;

      try
      {
         DateTime value = customDateTimePicker1->Value;
         SetColumnValueAtRow( dataSource, rowNum, value );
      }
      catch ( Exception^ ) 
      {
         Abort( rowNum );
         return false;
      }

      Invalidate();
      return true;
   }

   virtual void Edit(
      CurrencyManager^ source,
      int rowNum,
      Rectangle bounds,
      bool /*readOnly*/,
      String^ /*displayText*/,
      bool cellIsVisible ) override
   {
      DateTime value =  (DateTime)
         GetColumnValueAtRow( source, rowNum );
      if ( cellIsVisible )
      {
         customDateTimePicker1->Bounds = Rectangle(
            bounds.X + 2, bounds.Y + 2,
            bounds.Width - 4, bounds.Height - 4 );
         customDateTimePicker1->Value = value;
         customDateTimePicker1->Visible = true;
         customDateTimePicker1->ValueChanged +=
            gcnew EventHandler( this, &DataGridTimePickerColumn::TimePickerValueChanged );
      }
      else
      {
         customDateTimePicker1->Value = value;
         customDateTimePicker1->Visible = false;
      }

      if ( customDateTimePicker1->Visible )
         DataGridTableStyle->DataGrid->Invalidate( bounds );

      customDateTimePicker1->Focus();
   }

   virtual System::Drawing::Size GetPreferredSize(
      Graphics^ /*g*/,
      Object^ /*value*/ ) override
   {
      return Size( 100, customDateTimePicker1->PreferredHeight + 4);
   }

   virtual int GetMinimumHeight() override
   {
      return customDateTimePicker1->PreferredHeight + 4;
   }

   virtual int GetPreferredHeight( Graphics^ /*g*/,
      Object^ /*value*/ ) override
   {
      return customDateTimePicker1->PreferredHeight + 4;
   }

   virtual void Paint( Graphics^ g,
      Rectangle bounds,
      CurrencyManager^ source,
      int rowNum ) override
   {
      Paint( g, bounds, source, rowNum, false );
   }

   virtual void Paint(
      Graphics^ g,
      Rectangle bounds,
      CurrencyManager^ source,
      int rowNum,
      bool alignToRight ) override
   {
      Paint(
         g, bounds,
         source,
         rowNum,
         Brushes::Red,
         Brushes::Blue,
         alignToRight );
   }

   virtual void Paint(
      Graphics^ g,
      Rectangle bounds,
      CurrencyManager^ source,
      int rowNum,
      Brush^ backBrush,
      Brush^ foreBrush,
      bool /*alignToRight*/ ) override
   {
      DateTime date =  (DateTime)
         GetColumnValueAtRow( source, rowNum );
      Rectangle rect = bounds;
      g->FillRectangle( backBrush, rect );
      rect.Offset( 0, 2 );
      rect.Height -= 2;
      g->DrawString( date.ToString( "d" ),
         this->DataGridTableStyle->DataGrid->Font,
         foreBrush, rect );
   }

   virtual void SetDataGridInColumn( DataGrid^ value ) override
   {
      DataGridColumnStyle::SetDataGridInColumn( value );
      if ( customDateTimePicker1->Parent != nullptr )
      {
         customDateTimePicker1->Parent->Controls->Remove
            ( customDateTimePicker1 );
      }
      if ( value != nullptr )
      {
         value->Controls->Add( customDateTimePicker1 );
      }
   }

private:
   void TimePickerValueChanged( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      // Remove the handler to prevent it from being called twice in a row.
      customDateTimePicker1->ValueChanged -=
         gcnew EventHandler( this, &DataGridTimePickerColumn::TimePickerValueChanged );
      this->isEditing = true;
      DataGridColumnStyle::ColumnStartedEditing( customDateTimePicker1 );
   }
};

public ref class MyForm: public Form
{
private:
   DataTable^ namesDataTable;
   DataGrid^ grid;
public:
   MyForm()
   {
      grid = gcnew DataGrid;

      InitForm();

      namesDataTable = gcnew DataTable( "NamesTable" );
      namesDataTable->Columns->Add( gcnew DataColumn( "Name" ) );
      DataColumn^ dateColumn = gcnew DataColumn
         ( "Date",DateTime::typeid );
      dateColumn->DefaultValue = DateTime::Today;
      namesDataTable->Columns->Add( dateColumn );
      DataSet^ namesDataSet = gcnew DataSet;
      namesDataSet->Tables->Add( namesDataTable );
      grid->DataSource = namesDataSet;
      grid->DataMember = "NamesTable";
      AddGridStyle();
      AddData();
   }

private:
   void AddGridStyle()
   {
      DataGridTableStyle^ myGridStyle = gcnew DataGridTableStyle;
      myGridStyle->MappingName = "NamesTable";
      DataGridTextBoxColumn^ nameColumnStyle =
         gcnew DataGridTextBoxColumn;
      nameColumnStyle->MappingName = "Name";
      nameColumnStyle->HeaderText = "Name";
      myGridStyle->GridColumnStyles->Add( nameColumnStyle );

      DataGridTimePickerColumn^ timePickerColumnStyle =
         gcnew DataGridTimePickerColumn;
      timePickerColumnStyle->MappingName = "Date";
      timePickerColumnStyle->HeaderText = "Date";
      timePickerColumnStyle->Width = 100;
      myGridStyle->GridColumnStyles->Add( timePickerColumnStyle );

      grid->TableStyles->Add( myGridStyle );
   }

   void AddData()
   {
      DataRow^ dRow = namesDataTable->NewRow();
      dRow->default[ "Name" ] = "Name 1";
      dRow->default[ "Date" ] = DateTime(2001,12,01);
      namesDataTable->Rows->Add( dRow );

      dRow = namesDataTable->NewRow();
      dRow->default[ "Name" ] = "Name 2";
      dRow->default[ "Date" ] = DateTime(2001,12,04);
      namesDataTable->Rows->Add( dRow );

      dRow = namesDataTable->NewRow();
      dRow->default[ "Name" ] = "Name 3";
      dRow->default[ "Date" ] = DateTime(2001,12,29);
      namesDataTable->Rows->Add( dRow );

      dRow = namesDataTable->NewRow();
      dRow->default[ "Name" ] = "Name 4";
      dRow->default[ "Date" ] = DateTime(2001,12,13);
      namesDataTable->Rows->Add( dRow );

      dRow = namesDataTable->NewRow();
      dRow->default[ "Name" ] = "Name 5";
      dRow->default[ "Date" ] = DateTime(2001,12,21);
      namesDataTable->Rows->Add( dRow );

      namesDataTable->AcceptChanges();
   }

   void InitForm()
   {
      this->Size = System::Drawing::Size( 500, 500 );
      grid->Size = System::Drawing::Size( 350, 250 );
      grid->TabStop = true;
      grid->TabIndex = 1;
      this->StartPosition = FormStartPosition::CenterScreen;
      this->Controls->Add( grid );
   }
};

[STAThread]
int main()
{
   Application::Run( gcnew MyForm );
}

using System;
using System.Data;
using System.Windows.Forms;
using System.Drawing;

// This example shows how to create your own column style that
// hosts a control, in this case, a DateTimePicker.
public class DataGridTimePickerColumn : DataGridColumnStyle
{
    private CustomDateTimePicker customDateTimePicker1 = 
        new CustomDateTimePicker();

    // The isEditing field tracks whether or not the user is
    // editing data with the hosted control.
    private bool isEditing;

    public DataGridTimePickerColumn() : base()
    {
        customDateTimePicker1.Visible = false;
    }

    protected override void Abort(int rowNum)
    {
        isEditing = false;
        customDateTimePicker1.ValueChanged -=
            new EventHandler(TimePickerValueChanged);
        Invalidate();
    }

    protected override bool Commit
        (CurrencyManager dataSource, int rowNum)
    {
        customDateTimePicker1.Bounds = Rectangle.Empty;

        customDateTimePicker1.ValueChanged -=
            new EventHandler(TimePickerValueChanged);

        if (!isEditing)
            return true;

        isEditing = false;

        try
        {
            DateTime value = customDateTimePicker1.Value;
            SetColumnValueAtRow(dataSource, rowNum, value);
        }
        catch (Exception)
        {
            Abort(rowNum);
            return false;
        }

        Invalidate();
        return true;
    }

    protected override void Edit(
        CurrencyManager source,
        int rowNum,
        Rectangle bounds,
        bool readOnly,
        string displayText,
        bool cellIsVisible)
    {
        DateTime value = (DateTime)
            GetColumnValueAtRow(source, rowNum);
        if (cellIsVisible)
        {
            customDateTimePicker1.Bounds = new Rectangle
                (bounds.X + 2, bounds.Y + 2,
                bounds.Width - 4, bounds.Height - 4);
            customDateTimePicker1.Value = value;
            customDateTimePicker1.Visible = true;
            customDateTimePicker1.ValueChanged +=
                new EventHandler(TimePickerValueChanged);
        }
        else
        {
            customDateTimePicker1.Value = value;
            customDateTimePicker1.Visible = false;
        }

        if (customDateTimePicker1.Visible)
            DataGridTableStyle.DataGrid.Invalidate(bounds);

        customDateTimePicker1.Focus();
    }

    protected override Size GetPreferredSize(
        Graphics g,
        object value)
    {
        return new Size(100, customDateTimePicker1.PreferredHeight + 4);
    }

    protected override int GetMinimumHeight()
    {
        return customDateTimePicker1.PreferredHeight + 4;
    }

    protected override int GetPreferredHeight(Graphics g,
        object value)
    {
        return customDateTimePicker1.PreferredHeight + 4;
    }

    protected override void Paint(Graphics g,
        Rectangle bounds,
        CurrencyManager source,
        int rowNum)
    {
        Paint(g, bounds, source, rowNum, false);
    }

    protected override void Paint(
        Graphics g,
        Rectangle bounds,
        CurrencyManager source,
        int rowNum,
        bool alignToRight)
    {
        Paint(
            g, bounds,
            source,
            rowNum,
            Brushes.Red,
            Brushes.Blue,
            alignToRight);
    }

    protected override void Paint(
        Graphics g,
        Rectangle bounds,
        CurrencyManager source,
        int rowNum,
        Brush backBrush,
        Brush foreBrush,
        bool alignToRight)
    {
        DateTime date = (DateTime)
            GetColumnValueAtRow(source, rowNum);
        Rectangle rect = bounds;
        g.FillRectangle(backBrush, rect);
        rect.Offset(0, 2);
        rect.Height -= 2;
        g.DrawString(date.ToString("d"),
            this.DataGridTableStyle.DataGrid.Font,
            foreBrush, rect);
    }

    protected override void SetDataGridInColumn(DataGrid value)
    {
        base.SetDataGridInColumn(value);
        if (customDateTimePicker1.Parent != null)
        {
            customDateTimePicker1.Parent.Controls.Remove
                (customDateTimePicker1);
        }
        if (value != null)
        {
            value.Controls.Add(customDateTimePicker1);
        }
    }

    private void TimePickerValueChanged(object sender, EventArgs e)
    {
        // Remove the handler to prevent it from being called twice in a row.
        customDateTimePicker1.ValueChanged -=
            new EventHandler(TimePickerValueChanged);
        this.isEditing = true;
        base.ColumnStartedEditing(customDateTimePicker1);
    }
}

public class CustomDateTimePicker : DateTimePicker
{
    protected override bool ProcessKeyMessage(ref Message m)
    {
        // Keep all the keys for the DateTimePicker.
        return ProcessKeyEventArgs(ref m);
    }
}

public class MyForm : Form
{
    private DataTable namesDataTable;
    private DataGrid grid = new DataGrid();
    public MyForm() : base()
    {
        InitForm();

        namesDataTable = new DataTable("NamesTable");
        namesDataTable.Columns.Add(new DataColumn("Name"));
        DataColumn dateColumn = new DataColumn
            ("Date", typeof(DateTime));
        dateColumn.DefaultValue = DateTime.Today;
        namesDataTable.Columns.Add(dateColumn);
        DataSet namesDataSet = new DataSet();
        namesDataSet.Tables.Add(namesDataTable);
        grid.DataSource = namesDataSet;
        grid.DataMember = "NamesTable";
        AddGridStyle();
        AddData();
    }

    private void AddGridStyle()
    {
        DataGridTableStyle myGridStyle = new DataGridTableStyle();
        myGridStyle.MappingName = "NamesTable";

        DataGridTextBoxColumn nameColumnStyle =
            new DataGridTextBoxColumn();
        nameColumnStyle.MappingName = "Name";
        nameColumnStyle.HeaderText = "Name";
        myGridStyle.GridColumnStyles.Add(nameColumnStyle);

        DataGridTimePickerColumn timePickerColumnStyle =
            new DataGridTimePickerColumn();
        timePickerColumnStyle.MappingName = "Date";
        timePickerColumnStyle.HeaderText = "Date";
        timePickerColumnStyle.Width = 100;
        myGridStyle.GridColumnStyles.Add(timePickerColumnStyle);

        grid.TableStyles.Add(myGridStyle);
    }

    private void AddData()
    {

        DataRow dRow = namesDataTable.NewRow();
        dRow["Name"] = "Name 1";
        dRow["Date"] = new DateTime(2001, 12, 01);
        namesDataTable.Rows.Add(dRow);

        dRow = namesDataTable.NewRow();
        dRow["Name"] = "Name 2";
        dRow["Date"] = new DateTime(2001, 12, 04);
        namesDataTable.Rows.Add(dRow);

        dRow = namesDataTable.NewRow();
        dRow["Name"] = "Name 3";
        dRow["Date"] = new DateTime(2001, 12, 29);
        namesDataTable.Rows.Add(dRow);

        dRow = namesDataTable.NewRow();
        dRow["Name"] = "Name 4";
        dRow["Date"] = new DateTime(2001, 12, 13);
        namesDataTable.Rows.Add(dRow);

        dRow = namesDataTable.NewRow();
        dRow["Name"] = "Name 5";
        dRow["Date"] = new DateTime(2001, 12, 21);
        namesDataTable.Rows.Add(dRow);

        namesDataTable.AcceptChanges();
    }

    private void InitForm()
    {
        this.Size = new Size(500, 500);
        grid.Size = new Size(350, 250);
        grid.TabStop = true;
        grid.TabIndex = 1;
        this.StartPosition = FormStartPosition.CenterScreen;
        this.Controls.Add(grid);
    }
 
    [STAThread]
    public static void Main()
    {
        Application.Run(new MyForm());
    }
}

Imports System.Data
Imports System.Windows.Forms
Imports System.Drawing
Imports System.ComponentModel
Imports System.Security.Permissions

' This example shows how to create your own column style that
' hosts a control, in this case, a DateTimePicker.
Public Class DataGridTimePickerColumn
    Inherits DataGridColumnStyle

    Private customDateTimePicker1 As New CustomDateTimePicker()

    ' The isEditing field tracks whether or not the user is
    ' editing data with the hosted control.
    Private isEditing As Boolean

    Public Sub New()
        customDateTimePicker1.Visible = False
    End Sub

    Protected Overrides Sub Abort(ByVal rowNum As Integer)
        isEditing = False
        RemoveHandler customDateTimePicker1.ValueChanged, _
            AddressOf TimePickerValueChanged
        Invalidate()
    End Sub

    Protected Overrides Function Commit _
        (ByVal dataSource As CurrencyManager, ByVal rowNum As Integer) _
        As Boolean

        customDateTimePicker1.Bounds = Rectangle.Empty

        RemoveHandler customDateTimePicker1.ValueChanged, _
            AddressOf TimePickerValueChanged

        If Not isEditing Then
            Return True
        End If
        isEditing = False

        Try
            Dim value As DateTime = customDateTimePicker1.Value
            SetColumnValueAtRow(dataSource, rowNum, value)
        Catch
        End Try

        Invalidate()
        Return True
    End Function

    Protected Overloads Overrides Sub Edit( _
        ByVal [source] As CurrencyManager, _
        ByVal rowNum As Integer, _
        ByVal bounds As Rectangle, _
        ByVal [readOnly] As Boolean, _
        ByVal displayText As String, _
        ByVal cellIsVisible As Boolean)

        Dim value As DateTime = _
        CType(GetColumnValueAtRow([source], rowNum), DateTime)
        If cellIsVisible Then
            customDateTimePicker1.Bounds = New Rectangle _
            (bounds.X + 2, bounds.Y + 2, bounds.Width - 4, _
            bounds.Height - 4)

            customDateTimePicker1.Value = value
            customDateTimePicker1.Visible = True
            AddHandler customDateTimePicker1.ValueChanged, _
            AddressOf TimePickerValueChanged
        Else
            customDateTimePicker1.Value = value
            customDateTimePicker1.Visible = False
        End If

        If customDateTimePicker1.Visible Then
            DataGridTableStyle.DataGrid.Invalidate(bounds)
        End If

        customDateTimePicker1.Focus()

    End Sub

    Protected Overrides Function GetPreferredSize( _
        ByVal g As Graphics, _
        ByVal value As Object) As Size

        Return New Size(100, customDateTimePicker1.PreferredHeight + 4)

    End Function

    Protected Overrides Function GetMinimumHeight() As Integer
        Return customDateTimePicker1.PreferredHeight + 4
    End Function

    Protected Overrides Function GetPreferredHeight( _
        ByVal g As Graphics, ByVal value As Object) As Integer

        Return customDateTimePicker1.PreferredHeight + 4

    End Function

    Protected Overloads Overrides Sub Paint( _
        ByVal g As Graphics, ByVal bounds As Rectangle, _
        ByVal [source] As CurrencyManager, ByVal rowNum As Integer)

        Paint(g, bounds, [source], rowNum, False)

    End Sub

    Protected Overloads Overrides Sub Paint(ByVal g As Graphics, _
        ByVal bounds As Rectangle, ByVal [source] As CurrencyManager, _
        ByVal rowNum As Integer, ByVal alignToRight As Boolean)

        Paint(g, bounds, [source], rowNum, Brushes.Red, _
            Brushes.Blue, alignToRight)

    End Sub

    Protected Overloads Overrides Sub Paint(ByVal g As Graphics, _
        ByVal bounds As Rectangle, ByVal [source] As CurrencyManager, _
        ByVal rowNum As Integer, ByVal backBrush As Brush, _
        ByVal foreBrush As Brush, ByVal alignToRight As Boolean)

        Dim [date] As DateTime = _
        CType(GetColumnValueAtRow([source], rowNum), DateTime)
        Dim rect As Rectangle = bounds
        g.FillRectangle(backBrush, rect)
        rect.Offset(0, 2)
        rect.Height -= 2
        g.DrawString([date].ToString("d"), _
            Me.DataGridTableStyle.DataGrid.Font, foreBrush, _
            RectangleF.FromLTRB(rect.X, rect.Y, rect.Right, rect.Bottom))

    End Sub

    Protected Overrides Sub SetDataGridInColumn(ByVal value As DataGrid)
        MyBase.SetDataGridInColumn(value)
        If (customDateTimePicker1.Parent IsNot Nothing) Then
            customDateTimePicker1.Parent.Controls.Remove(customDateTimePicker1)
        End If
        If (value IsNot Nothing) Then
            value.Controls.Add(customDateTimePicker1)
        End If
    End Sub

    Private Sub TimePickerValueChanged( _
        ByVal sender As Object, ByVal e As EventArgs)

        ' Remove the handler to prevent it from being called twice in a row.
        RemoveHandler customDateTimePicker1.ValueChanged, _
            AddressOf TimePickerValueChanged
        Me.isEditing = True
        MyBase.ColumnStartedEditing(customDateTimePicker1)

    End Sub

End Class

Public Class CustomDateTimePicker
    Inherits DateTimePicker

    <SecurityPermissionAttribute( _
    SecurityAction.LinkDemand, Flags := SecurityPermissionFlag.UnmanagedCode)> _
    Protected Overrides Function ProcessKeyMessage(ByRef m As Message) As Boolean
        ' Keep all the keys for the DateTimePicker.
        Return ProcessKeyEventArgs(m)
    End Function

End Class

Public Class MyForm
    Inherits Form

    Private namesDataTable As DataTable
    Private myGrid As DataGrid = New DataGrid()

    Public Sub New()

        InitForm()

        namesDataTable = New DataTable("NamesTable")
        namesDataTable.Columns.Add(New DataColumn("Name"))
        Dim dateColumn As DataColumn = _
             New DataColumn("Date", GetType(DateTime))
        dateColumn.DefaultValue = DateTime.Today
        namesDataTable.Columns.Add(dateColumn)
        Dim namesDataSet As DataSet = New DataSet()
        namesDataSet.Tables.Add(namesDataTable)
        myGrid.DataSource = namesDataSet
        myGrid.DataMember = "NamesTable"
        AddGridStyle()
        AddData()

    End Sub

    Private Sub AddGridStyle()
        Dim myGridStyle As DataGridTableStyle = _
                    New DataGridTableStyle()
        myGridStyle.MappingName = "NamesTable"

        Dim nameColumnStyle As DataGridTextBoxColumn = _
            New DataGridTextBoxColumn()
        nameColumnStyle.MappingName = "Name"
        nameColumnStyle.HeaderText = "Name"
        myGridStyle.GridColumnStyles.Add(nameColumnStyle)

        Dim customDateTimePicker1ColumnStyle As DataGridTimePickerColumn = _
            New DataGridTimePickerColumn()
        customDateTimePicker1ColumnStyle.MappingName = "Date"
        customDateTimePicker1ColumnStyle.HeaderText = "Date"
        customDateTimePicker1ColumnStyle.Width = 100
        myGridStyle.GridColumnStyles.Add(customDateTimePicker1ColumnStyle)

        myGrid.TableStyles.Add(myGridStyle)
    End Sub

    Private Sub AddData()
        Dim dRow As DataRow = namesDataTable.NewRow()
        dRow("Name") = "Name 1"
        dRow("Date") = New DateTime(2001, 12, 1)
        namesDataTable.Rows.Add(dRow)

        dRow = namesDataTable.NewRow()
        dRow("Name") = "Name 2"
        dRow("Date") = New DateTime(2001, 12, 4)
        namesDataTable.Rows.Add(dRow)

        dRow = namesDataTable.NewRow()
        dRow("Name") = "Name 3"
        dRow("Date") = New DateTime(2001, 12, 29)
        namesDataTable.Rows.Add(dRow)

        dRow = namesDataTable.NewRow()
        dRow("Name") = "Name 4"
        dRow("Date") = New DateTime(2001, 12, 13)
        namesDataTable.Rows.Add(dRow)

        dRow = namesDataTable.NewRow()
        dRow("Name") = "Name 5"
        dRow("Date") = New DateTime(2001, 12, 21)
        namesDataTable.Rows.Add(dRow)

        namesDataTable.AcceptChanges()
    End Sub

    Private Sub InitForm()
        Me.Size = New Size(500, 500)
        myGrid.Size = New Size(350, 250)
        myGrid.TabStop = True
        myGrid.TabIndex = 1
        Me.StartPosition = FormStartPosition.CenterScreen
        Me.Controls.Add(myGrid)
    End Sub

    <STAThread()> _
    Public Shared Sub Main()
        Application.Run(New MyForm())
    End Sub

End Class

Commenti

La raccolta di DataGridColumnStyle oggetti (il GridColumnStylesCollection) viene accessibile tramite la System.Windows.Forms.DataGrid proprietà del TableStyles controllo.

Il System.Windows.Forms.DataGrid controllo crea automaticamente una raccolta di DataGridColumnStyle oggetti quando si imposta la proprietà su un'origine DataSource dati appropriata. Gli oggetti creati in realtà sono istanze di una delle classi seguenti che ereditano da DataGridColumnStyle: DataGridBoolColumn o DataGridTextBoxColumn classe.

Per formattare la visualizzazione dei dati, impostare la Format proprietà della DataGridTextBoxColumn classe su uno dei valori di formattazione. Per altre informazioni sui valori di formattazione validi, vedere Formattazione dei tipie stringhe di formato data e ora personalizzate.

È anche possibile creare il proprio set di DataGridColumnStyle oggetti e aggiungerli all'oggetto GridColumnStylesCollection. In tal caso, è necessario impostare lo MappingName stile di ogni colonna su ColumnName un DataColumn oggetto per sincronizzare la visualizzazione delle colonne con i dati effettivi.

Quando una delle classi derivate viene creata da un System.Windows.Forms.DataGrid controllo, la classe creata dipende DataType dall'oggetto DataColumn associato all'oggetto DataGridColumnStyle . Ad esempio, un DataColumn oggetto con il relativo DataType set su System.Boolean verrà associato a un DataGridBoolColumnoggetto . Per determinare il tipo di qualsiasi DataGridColumnStyle, usare il GetType metodo .

Per creare classi di colonna personalizzate, è possibile ereditare da DataGridColumnStyle. È possibile eseguire questa operazione per creare colonne speciali che ospitano controlli, come illustrato dalla DataGridTextBox classe, che ospita il TextBox controllo. Ad esempio, è possibile ospitare un Image controllo per visualizzare immagini in colonne oppure creare il proprio controllo utente per ospitare nella colonna.

La funzionalità dell'oggetto DataGridColumnStyleDataColumnnon deve essere confusa con quella di . DataColumn Mentre contiene le proprietà e i metodi appropriati per la creazione dello schema di una tabella dati, contiene DataGridColumnStyle le proprietà e i metodi correlati all'aspetto di una singola colonna sullo schermo.

Se una riga contiene un DBNull.Valueoggetto , il testo visualizzato nella colonna può essere impostato con la NullText proprietà .

La DataGridColumnStyle classe consente inoltre di specificare il comportamento di una colonna mentre i relativi dati vengono modificati. I BeginUpdate metodi e EndUpdate sospendono temporaneamente il disegno della colonna mentre vengono eseguiti aggiornamenti di grandi dimensioni ai dati della colonna. Senza questa funzionalità, ogni modifica in ogni cella della griglia verrebbe immediatamente disegnata; questo potrebbe distrarre l'utente e una responsabilità delle prestazioni.

Diversi metodi consentono il monitoraggio della colonna durante la modifica da parte dell'utente, inclusi gli Edit eventi e Commit .

La maggior parte delle proprietà e dei metodi della classe è personalizzata per controllare l'aspetto di una colonna. Tuttavia, alcuni elementi, ad esempio GetColumnValueAtRow e SetColumnValueAtRow consentono di esaminare e modificare il valore in una cella specificata.

Note per gli implementatori

Quando si eredita da DataGridColumnStyle, è necessario eseguire l'override dei membri seguenti: Abort(Int32), Commit(CurrencyManager, Int32), Edit(CurrencyManager, Int32, Rectangle, Boolean), e Paint(Graphics, Rectangle, CurrencyManager, Int32) (due volte).

Costruttori

Proprietà

Metodi

Eventi

Implementazioni dell'interfaccia esplicita

Si applica a

Vedi anche

• DataColumn
• DataGrid
• DataGridBoolColumn
• DataGridTextBox
• DataGridTableStyle
• DataView
• GridColumnStylesCollection