DataGridColumnCollection Class

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

A collection of DataGridColumn-derived column objects that represent the columns in a DataGrid control. This class cannot be inherited.

public ref class DataGridColumnCollection sealed : System::Collections::ICollection, System::Web::UI::IStateManager
public sealed class DataGridColumnCollection : System.Collections.ICollection, System.Web.UI.IStateManager
type DataGridColumnCollection = class
    interface ICollection
    interface IEnumerable
    interface IStateManager
Public NotInheritable Class DataGridColumnCollection
Implements ICollection, IStateManager
Inheritance
Object
DataGridColumnCollection
Implements
ICollection IEnumerable IStateManager

Examples

The following code example demonstrates how to use the DataGridColumnCollection collection to dynamically add a column to the DataGrid control. Note that the Columns property of the DataGrid control is an instance of the DataGridColumnCollection class.


<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script runat="server">

      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;

      }
 
      void Page_Load(Object sender, EventArgs e) 
      {

         // Create a DataGrid control.
         DataGrid ItemsGrid = new DataGrid();

         // Set the properties of the DataGrid.
         ItemsGrid.ID = "ItemsGrid";
         ItemsGrid.BorderColor = System.Drawing.Color.Black;
         ItemsGrid.CellPadding = 3;
         ItemsGrid.AutoGenerateColumns = false;

         // Set the styles for the DataGrid.
         ItemsGrid.HeaderStyle.BackColor = 
             System.Drawing.Color.FromArgb(0x0000aaaa);

         // Create the columns for the DataGrid control. The DataGrid
         // columns are dynamically generated. Therefore, the columns   
         // must be re-created each time the page is refreshed.
         
         // Create and add the columns to the collection.
         ItemsGrid.Columns.Add(CreateBoundColumn("IntegerValue", "Item"));
         ItemsGrid.Columns.Add(
             CreateBoundColumn("StringValue", "Description"));
         ItemsGrid.Columns.Add(
             CreateBoundColumn("CurrencyValue", "Price", "{0:c}", 
             HorizontalAlign.Right));
         ItemsGrid.Columns.Add(
             CreateLinkColumn("http://www.microsoft.com", "_self", 
             "Microsoft", "Related link"));
        
         // Specify the data source and bind it to the control.
         ItemsGrid.DataSource = CreateDataSource();
         ItemsGrid.DataBind();

         // Add the DataGrid control to the Controls collection of 
         // the PlaceHolder control.
         Place.Controls.Add(ItemsGrid);

      }

      BoundColumn CreateBoundColumn(String DataFieldValue, 
          String HeaderTextValue)
      {

         // This version of the CreateBoundColumn method sets only the
         // DataField and HeaderText properties.

         // Create a BoundColumn.
         BoundColumn column = new BoundColumn();

         // Set the properties of the BoundColumn.
         column.DataField = DataFieldValue;
         column.HeaderText = HeaderTextValue;

         return column;

      }

      BoundColumn CreateBoundColumn(String DataFieldValue, 
          String HeaderTextValue, String FormatValue, 
          HorizontalAlign AlignValue)
      {

         // This version of CreateBoundColumn method sets the DataField,
         // HeaderText, and DataFormatString properties. It also sets the 
         // HorizontalAlign property of the ItemStyle property of the column. 

         // Create a BoundColumn using the overloaded CreateBoundColumn method.
         BoundColumn column = CreateBoundColumn(DataFieldValue, HeaderTextValue);

         // Set the properties of the BoundColumn.
         column.DataFormatString = FormatValue;
         column.ItemStyle.HorizontalAlign = AlignValue;

         return column;

      }

      HyperLinkColumn CreateLinkColumn(String NavUrlValue, 
          String TargetValue, String TextValue, String HeaderTextValue)
      {

         // Create a BoundColumn.
         HyperLinkColumn column = new HyperLinkColumn();

         // Set the properties of the ButtonColumn.
         column.NavigateUrl = NavUrlValue;
         column.Target = TargetValue;
         column.Text = TextValue;
         column.HeaderText = HeaderTextValue;

         return column;

      }

   </script>
 
<head runat="server">
    <title>DataGrid Constructor Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGrid Constructor Example</h3>
 
      <b>Product List</b>

      <asp:PlaceHolder id="Place"
           runat="server"/>
 
   </form>
 
</body>
</html>


<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script runat="server">

      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(string)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(double)))
 
         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 to 8 
        
            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)

         Next i
 
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
      Sub Page_Load(sender As Object, e As EventArgs) 

         ' Create a DataGrid control.
         Dim ItemsGrid As DataGrid = New DataGrid()

         ' Set the properties of the DataGrid.
         ItemsGrid.ID = "ItemsGrid"
         ItemsGrid.BorderColor = System.Drawing.Color.Black
         ItemsGrid.CellPadding = 3
         ItemsGrid.AutoGenerateColumns = False

         ' Set the styles for the DataGrid.
         ItemsGrid.HeaderStyle.BackColor = System.Drawing.Color.FromArgb(&H0000aaaa)

         ' Create the columns for the DataGrid control. The DataGrid
         ' columns are dynamically generated. Therefore, the columns   
         ' must be re-created each time the page is refreshed.
         
         ' Create and add the columns to the collection.
         ItemsGrid.Columns.Add(CreateBoundColumn("IntegerValue", "Item"))
         ItemsGrid.Columns.Add( _
             CreateBoundColumn("StringValue", "Description"))
         ItemsGrid.Columns.Add( _
             CreateBoundColumn("CurrencyValue", "Price", "{0:c}", _
             HorizontalAlign.Right))
         ItemsGrid.Columns.Add( _
             CreateLinkColumn("http:'www.microsoft.com", "_self", _
             "Microsoft", "Related link"))
        
         ' Specify the data source and bind it to the control.     
         ItemsGrid.DataSource = CreateDataSource()
         ItemsGrid.DataBind()

         ' Add the DataGrid control to the Controls collection of 
         ' the PlaceHolder control.
         Place.Controls.Add(ItemsGrid)

      End Sub

      Function CreateBoundColumn(DataFieldValue As String, HeaderTextValue As String) As BoundColumn

         ' This version of CreateBoundColumn method sets only the 
         ' DataField and HeaderText properties.

         ' Create a BoundColumn.
         Dim column As BoundColumn = New BoundColumn()

         ' Set the properties of the BoundColumn.
         column.DataField = DataFieldValue
         column.HeaderText = HeaderTextValue

         Return column

      End Function

      Function CreateBoundColumn(DataFieldValue As String, _
          HeaderTextValue As String, FormatValue As String, _
          AlignValue As HorizontalAlign) As BoundColumn

         ' This version of CreateBoundColumn method sets the DataField,
         ' HeaderText, and DataFormatString properties. It also sets the 
         ' HorizontalAlign property of the ItemStyle property of the column. 

         ' Create a BoundColumn using the overloaded CreateBoundColumn method.
         Dim column As BoundColumn = CreateBoundColumn(DataFieldValue, HeaderTextValue)

         ' Set the properties of the BoundColumn.
         column.DataFormatString = FormatValue
         column.ItemStyle.HorizontalAlign = AlignValue

         Return column

      End Function

      Function CreateLinkColumn(NavUrlValue As String, TargetValue As String, _
         TextValue As String, HeaderTextValue As String) As HyperLinkColumn 

         ' Create a BoundColumn.
         Dim column As HyperLinkColumn = New HyperLinkColumn()

         ' Set the properties of the ButtonColumn.
         column.NavigateUrl = NavUrlValue
         column.Target = TargetValue
         column.Text = TextValue
         column.HeaderText = HeaderTextValue

         Return column

      End Function

   </script>
 
<head runat="server">
    <title>DataGrid Constructor Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGrid Constructor Example</h3>
 
      <b>Product List</b>

      <asp:PlaceHolder id="Place"
           runat="server"/>
 
   </form>
 
</body>
</html>

Remarks

Use the DataGridColumnCollection collection to programmatically manage a collection of DataGridColumn-derived column objects. These objects represent the columns in a DataGrid control. You can add, remove, or insert columns in the DataGridColumnCollection collection.

Note

When the AutoGenerateColumns property is set to true, the columns created by the DataGrid control are not added to the Columns collection.

The DataGrid control does not store the contents of its Columns collection in the view state. To add or remove a column dynamically, you must programmatically add or remove the column every time the page is refreshed. Provide a Page_Init function that adds or removes the column before the DataGrid control's state is reloaded and the control is rebuilt. Otherwise, the changes to the Columns collection are not reflected in the DataGrid control when it is displayed.

Note

Although you can programmatically add columns to or remove columns from the Columns collection of the DataGrid control, it is easier to list the columns statically and then use the Visible property to display or hide each column.

The order of the columns in the collection determines the order that the columns are displayed in the DataGrid control.

The following table lists the different column classes that derive from the DataGridColumn class.

Column Class Description
BoundColumn A column that is bound to a field in a data source. It displays each item in the field as text. This is the default column type for the DataGrid control.
ButtonColumn A column that displays a command button for each item in the column. This allows you to create a column of custom button controls, such as Add or Remove buttons.
EditCommandColumn A column that contains editing commands for each item in the column.
HyperLinkColumn A column that displays each item in the column as a hyperlink. The contents of the column can be bound to a field in a data source, or to static text.
TemplateColumn A column that displays each item in the column according to a specified template. This allows you to control the content of the column, for example to display images.

Note

The DataGridColumn class is the base class for the column classes listed. It is not used directly in the DataGridColumnCollection collection.

Constructors

DataGridColumnCollection(DataGrid, ArrayList)

Initializes a new instance of the DataGridColumnCollection class.

Properties

Count

Gets the number of columns in the DataGridColumnCollection collection.
IsReadOnly

Gets a value that indicates whether the columns in the DataGridColumnCollection collection can be modified.
IsSynchronized

Gets a value indicating whether access to the DataGridColumnCollection collection is synchronized (thread safe).
Item[Int32]

Gets a DataGridColumn-derived column object from the DataGridColumnCollection collection at the specified index.
SyncRoot

Gets the object that can be used to synchronize access to the DataGridColumnCollection collection.

Methods

Add(DataGridColumn)

Appends the specified DataGridColumn-derived column object to the end of the DataGridColumnCollection collection.
AddAt(Int32, DataGridColumn)

Inserts a DataGridColumn-derived column object in the DataGridColumnCollection collection at the specified index.
Clear()

Removes all DataGridColumn-derived column objects from the DataGridColumnCollection collection.
CopyTo(Array, Int32)

Copies the items from the DataGridColumnCollection collection to the specified Array, starting at the specified index in the Array.
Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator()

Returns a IEnumerator interface that contains all the DataGridColumn-derived column objects in the DataGridColumnCollection collection.
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
IndexOf(DataGridColumn)

Returns the index of the specified DataGridColumn-derived column object from the DataGridColumnCollection collection.
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
Remove(DataGridColumn)

Removes the specified DataGridColumn-derived column object from the DataGridColumnCollection collection.
RemoveAt(Int32)

Removes a DataGridColumn-derived column object from the DataGridColumnCollection collection at the specified index.
ToString()

Returns a string that represents the current object.

(Inherited from Object)

Explicit Interface Implementations

IStateManager.IsTrackingViewState

Gets a value indicating whether the collection is tracking its view-state changes.
IStateManager.LoadViewState(Object)

Loads the previously saved state.
IStateManager.SaveViewState()

Returns an object containing state changes.
IStateManager.TrackViewState()

Starts tracking state changes.

Extension Methods

Cast<TResult>(IEnumerable)

Casts the elements of an IEnumerable to the specified type.
OfType<TResult>(IEnumerable)

Filters the elements of an IEnumerable based on a specified type.
AsParallel(IEnumerable)

Enables parallelization of a query.
AsQueryable(IEnumerable)

Converts an IEnumerable to an IQueryable.

Applies to

See also