DataSourceDesigner Classe

Definizione

public ref class DataSourceDesigner : System::Web::UI::Design::ControlDesigner, System::Web::UI::Design::IDataSourceDesigner

public class DataSourceDesigner : System.Web.UI.Design.ControlDesigner, System.Web.UI.Design.IDataSourceDesigner

type DataSourceDesigner = class
    inherit ControlDesigner
    interface IDataSourceDesigner

Public Class DataSourceDesigner
Inherits ControlDesigner
Implements IDataSourceDesigner

Ereditarietà

Object

ComponentDesigner

HtmlControlDesigner

ControlDesigner

DataSourceDesigner

Derivato

System.Web.UI.Design.WebControls.EntityDataSourceDesigner

System.Web.UI.Design.WebControls.LinqDataSourceDesigner

System.Web.UI.Design.WebControls.ObjectDataSourceDesigner

System.Web.UI.Design.WebControls.SqlDataSourceDesigner

Implementazioni

IDataSourceDesigner

Esempio

Nell'esempio di codice seguente viene illustrato come usare un controllo origine dati personalizzato con diverse altre classi personalizzate, come illustrato nella tabella seguente.

Dopo aver compilato l'esempio di codice, aprire la pagina .aspx nella visualizzazione Progettazione e quindi impostare la DataSourceID proprietà sull'ID del controllo origine dati personalizzato.

using System;
using System.Data;
using System.Security.Permissions;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.Design;
using System.Web.UI.Design.WebControls;
using System.ComponentModel;
using System.ComponentModel.Design;

namespace ASPNet.Design.Samples_CS
{
    [Designer(typeof(CustomDataSourceDesigner)),
        ToolboxData("<{0}:CustomDataSource runat=\"server\"></{0}:CustomDataSource>")]
    public class CustomDataSource : ObjectDataSource
    {
        private ObjectDataSourceView _view = null;
        private string _defaultViewName = "BookList";

        public CustomDataSource() : base() { }

        // Gets a view by name
        protected override DataSourceView GetView(string viewName)
        {
            // This data source only allows one view
            if (viewName != _defaultViewName)
            {
                return null;
            }
            else if (_view == null)
            {
                _view = new CustomDataSourceView(this, 
                    _defaultViewName, HttpContext.Current);
            }

            return _view;
        }

        // Gets a list of view names for this class
        protected override ICollection GetViewNames()
        {
            ArrayList ar = new ArrayList(1);
            ar.Add(_defaultViewName);
            return ar as ICollection;
        }
    }

    // The runtime data source view
    public class CustomDataSourceView : ObjectDataSourceView
    {
        private ArrayList _data = null;

        public CustomDataSourceView(CustomDataSource owner, 
            string viewName, HttpContext context)
            : base(owner, viewName, context)
        {
            owner.SelectCountMethod = "GetCount";
        }

        // This method would typically get a set of live data  
        // rather than create some dummy data
        protected override IEnumerable ExecuteSelect(
            DataSourceSelectArguments arguments)
        {
            if (_data == null)
            {
                // Create a set of runtime fake data
                _data = new ArrayList();
                _data.Add(new BookItem("ID_1", "Runtime Title 01"));
                _data.Add(new BookItem("ID_2", "Runtime Title 02"));
                _data.Add(new BookItem("ID_3", "Runtime Title 03"));
            }

            return _data as IEnumerable;
        }

        // Allow getting the record count
        public override bool CanRetrieveTotalRowCount
        {
            get { return true; }
        }

        // Returns the number of records in the current set of data
        public int GetCount()
        {
            if (_data == null)
                return 0;
            else
                return _data.Count;
        }
        
        // Do not allow deletions
        public override bool CanDelete
        {
            get { return false; }
        }
        // Do not allow insertions
        public override bool CanInsert
        {
            get { return false; }
        }
        // Do not allow paging
        public override bool CanPage
        {
            get { return false; }
        }
        // Do not allow sorting
        public override bool CanSort
        {
            get { return false; }
        }
        // Do not allow updating
        public override bool CanUpdate
        {
            get { return false; }
        }
    }

    // A class to define each record of the data
    public class BookItem
    {
        private string _id;
        private string _title;

        public BookItem(string id, string title)
        {
            _id = id;
            _title = title;
        }

        public string ID
        {
            get { return _id; }
        }
        public string Title
        {
            get { return _title; }
            set { _title = value; }
        }
    }

    // Custom designer for the CustomDataSource control.
    public class CustomDataSourceDesigner : DataSourceDesigner
    {
        private CustomDataSource _control;
        private string _defaultViewName = "BookList";
        private CustomDesignDataSourceView _view = null;

        // Initialize the designer
        public override void Initialize(IComponent component)
        {
            base.Initialize(component);
            _control = (CustomDataSource)Component;
        }

        // Get a view
        public override DesignerDataSourceView GetView(string viewName)
        {
            if (!viewName.Equals(_defaultViewName))
                return null;

            _view ??= new CustomDesignDataSourceView(this,
                _defaultViewName);

            return _view;
        }

        // Get a list of view names
        public override string[] GetViewNames()
        {
            return new string[] { "BookList" };
        }

        // Do not allow refreshing the schema
        public override bool CanRefreshSchema
        {
            get { return false; }
        }
        // Do not allow resizing
        public override bool AllowResize
        {
            get { return false; }
        }
    }

    // A design-time data source view
    public class CustomDesignDataSourceView : DesignerDataSourceView
    {
        private ArrayList _data = null;

        public CustomDesignDataSourceView(
            CustomDataSourceDesigner owner, string viewName)
            : base(owner, viewName)
        {}

        // Get data for design-time display
        public override IEnumerable GetDesignTimeData(
            int minimumRows, out bool isSampleData)
        {
            if (_data == null)
            {
                // Create a set of design-time fake data
                _data = new ArrayList();
                for (int i = 1; i <= minimumRows; i++)
                {
                    _data.Add(new BookItem("ID_" + i.ToString(),
                        "Design-Time Title 0" + i.ToString()));
                }
            }
            isSampleData = true;
            return _data as IEnumerable;
        }

        public override IDataSourceViewSchema Schema
        {
            get { return new BookListViewSchema(); }
        }

        // Allow getting the record count
        public override bool CanRetrieveTotalRowCount
        {
            get { return true; }
        }
        // Do not allow deletions
        public override bool CanDelete
        {
            get { return false; }
        }
        // Do not allow insertions
        public override bool CanInsert
        {
            get { return false; }
        }
        // Do not allow updates
        public override bool CanUpdate
        {
            get { return false; }
        }
        // Do not allow paging
        public override bool CanPage
        {
            get { return false; }
        }
        // Do not allow sorting
        public override bool CanSort
        {
            get { return false; }
        }
    }

    // A custom View Schema class
    public class BookListViewSchema : IDataSourceViewSchema
    {
        public BookListViewSchema()
        { }

        // The name of this View Schema
        public string Name
        {
            get { return "BookList"; }
        }

        // Build a Field Schema array
        public IDataSourceFieldSchema[] GetFields()
        {
            IDataSourceFieldSchema[] fields = new IDataSourceFieldSchema[2];
            fields[0] = new CustomIDFieldSchema();
            fields[1] = new CustomTitleFieldSchema();
            return fields;
        }
        // There are no child views, so return null
        public IDataSourceViewSchema[] GetChildren()
        {
            return null;
        }
    }

    // A custom Field Schema class for ID
    public class CustomIDFieldSchema : IDataSourceFieldSchema
    {
        public CustomIDFieldSchema()
        { }

        // Name is ID
        public string Name
        {
            get { return "ID"; }
        }
        // Data type is string
        public Type DataType
        {
            get { return typeof(string); }
        }
        // This is not an Identity field
        public bool Identity
        {
            get { return false; }
        }
        // This field is read only
        public bool IsReadOnly
        {
            get { return true; }
        }
        // This field is unique
        public bool IsUnique
        {
            get { return true; }
        }
        // This field can't be longer than 20
        public int Length
        {
            get { return 20; }
        }
        // This field can't be null
        public bool Nullable
        {
            get { return false; }
        }
        // This is a Primary Key
        public bool PrimaryKey
        {
            get { return true; }
        }

        // These properties do not apply
        public int Precision
        {
            get { return -1; }
        }
        public int Scale
        {
            get { return -1; }
        }
    }
    
    // A custom Field Schema class for Title
    public class CustomTitleFieldSchema : IDataSourceFieldSchema
    {
        public CustomTitleFieldSchema()
        { }

        // Name is Title
        public string Name
        {
            get { return "Title"; }
        }
        // Type is string
        public Type DataType
        {
            get { return typeof(string); }
        }
        // This is not an Identity field
        public bool Identity
        {
            get { return false; }
        }
        // This field is not read only
        public bool IsReadOnly
        {
            get { return false; }
        }
        // This field is not unique
        public bool IsUnique
        {
            get { return false; }
        }
        // This field can't be longer than 100
        public int Length
        {
            get { return 100; }
        }
        // This field can't be null
        public bool Nullable
        {
            get { return false; }
        }
        // This is not the Primary Key
        public bool PrimaryKey
        {
            get { return false; }
        }

        // These properties do not apply
        public int Precision
        {
            get { return -1; }
        }
        public int Scale
        {
            get { return -1; }
        }
    }
}

Imports System.Data
Imports System.Security.Permissions
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.Design
Imports System.Web.UI.Design.WebControls
Imports System.ComponentModel
Imports System.ComponentModel.Design

Namespace ASPNet.Design.Samples_VB
    <Designer(GetType(CustomDataSourceDesigner)), _
        ToolboxData("<{0}:CustomDataSource runat=""server""></{0}:CustomDataSource>")> _
    Public Class CustomDataSource
        Inherits ObjectDataSource

        Dim _defaultViewName As String = "BookList"
        Dim _view As ObjectDataSourceView = Nothing

        Public Sub New()
            MyBase.New()
        End Sub

        ' Gets a view by name
        Protected Overrides Function GetView(ByVal viewName As String) As DataSourceView
            ' This data source only allows one view
            If Not (viewName.Equals(_defaultViewName)) Then
                Return Nothing
            ElseIf IsNothing(_view) Then
                _view = New CustomDataSourceView(Me, _
                    _defaultViewName, HttpContext.Current)
            End If

            Return _view
        End Function

        ' Gets a list of view names for this class
        Protected Overrides Function GetViewNames() As ICollection
            Dim ar As New ArrayList()
            ar.Add(_defaultViewName)
            Return CType(ar, ICollection)
        End Function

    End Class

    ' The runtime data source view
    Public Class CustomDataSourceView
        Inherits ObjectDataSourceView

        Dim _data As ArrayList = Nothing

        Public Sub New(ByVal owner As CustomDataSource, ByVal viewName As String, ByVal context As HttpContext)
            MyBase.New(owner, viewName, context)
            owner.SelectCountMethod = "GetCount"
        End Sub

        ' This method would typically get a set of live data
        ' rather than create some dummy data
        Protected Overrides Function ExecuteSelect(ByVal arguments As DataSourceSelectArguments) As System.Collections.IEnumerable
            If (IsNothing(_data)) Then
                _data = New ArrayList()
                _data.Add(New BookItem("ID_1", "Runtime Title 01"))
                _data.Add(New BookItem("ID_2", "Runtime Title 02"))
                _data.Add(New BookItem("ID_3", "Runtime Title 03"))
            End If
            Return CType(_data, IEnumerable)
        End Function

        ' Allow getting the record count
        Public Overrides ReadOnly Property CanRetrieveTotalRowCount() As Boolean
            Get
                Return True
            End Get
        End Property

        ' Returns the number of records in the current set of data
        Public ReadOnly Property GetCount() As Integer
            Get
                If IsNothing(_data) Then
                    Return 0
                Else
                    Return _data.Count
                End If
            End Get
        End Property
        ' Do not allow deletions
        Public Overrides ReadOnly Property CanDelete() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow insertions
        Public Overrides ReadOnly Property CanInsert() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow paging
        Public Overrides ReadOnly Property CanPage() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow sorting
        Public Overrides ReadOnly Property CanSort() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow updating
        Public Overrides ReadOnly Property CanUpdate() As Boolean
            Get
                Return False
            End Get
        End Property

    End Class

    ' A class to define a record of the data
    Public Class BookItem
        Private _id As String
        Private _title As String

        Public Sub New(ByVal id As String, ByVal title As String)
            _id = id
            _title = title
        End Sub

        Public ReadOnly Property ID() As String
            Get
                Return _id
            End Get
        End Property

        Public Property Title() As String
            Get
                Return _title
            End Get
            Set(ByVal value As String)
                _title = value
            End Set
        End Property
    End Class

    ' Custom designer for the CustomDataSource control.
    Public Class CustomDataSourceDesigner
        Inherits DataSourceDesigner

        Private _control As CustomDataSource = Nothing
        Private _defaultViewName As String = "BookList"
        Private _view As CustomDesignDataSourceView = Nothing

        Public Overrides Sub Initialize(ByVal cmponent As IComponent)
            MyBase.Initialize(cmponent)
            _control = CType(cmponent, CustomDataSource)
        End Sub

        ' Get a view
        Public Overrides Function GetView(ByVal viewName As String) As DesignerDataSourceView
            If Not (viewName.Equals(_defaultViewName)) Then
                Return Nothing
            ElseIf IsNothing(_view) Then
                _view = New CustomDesignDataSourceView(Me, _
                    _defaultViewName)
            End If

            Return _view
        End Function

        ' Get a list of view names
        Public Overrides Function GetViewNames() As String()
            Return New String() {"BookList"}
        End Function

        ' Don't allow refreshing the schema
        Public Overrides ReadOnly Property CanRefreshSchema() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow resizing
        Public Overrides ReadOnly Property AllowResize() As Boolean
            Get
                Return False
            End Get
        End Property
    End Class

    ' A     design-time data source view
    Public Class CustomDesignDataSourceView
        Inherits DesignerDataSourceView

        Private _data As ArrayList = Nothing

        Public Sub New(ByVal owner As CustomDataSourceDesigner, ByVal viewName As String)
            MyBase.New(owner, viewName)
        End Sub

        ' Get data for design-time display
        Public Overrides Function GetDesignTimeData( _
            ByVal minimumRows As Integer, _
            ByRef isSampleData As Boolean) As IEnumerable

            If IsNothing(_data) Then
                ' Create a set of design-time fake data
                _data = New ArrayList()
                Dim i As Integer
                For i = 1 To minimumRows
                    _data.Add(New BookItem("ID_" & i.ToString(), _
                        "Design-Time Title 0" & i.ToString()))
                Next
            End If
            isSampleData = True
            Return CType(_data, IEnumerable)
        End Function

        Public Overrides ReadOnly Property Schema() As IDataSourceViewSchema
            Get
                Return New BookListViewSchema()
            End Get
        End Property

        ' Allow getting the record count
        Public Overrides ReadOnly Property CanRetrieveTotalRowCount() As Boolean
            Get
                Return True
            End Get
        End Property
        ' Do not allow deletions
        Public Overrides ReadOnly Property CanDelete() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow insertions
        Public Overrides ReadOnly Property CanInsert() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow updates
        Public Overrides ReadOnly Property CanUpdate() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow paging
        Public Overrides ReadOnly Property CanPage() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow sorting
        Public Overrides ReadOnly Property CanSort() As Boolean
            Get
                Return False
            End Get
        End Property
    End Class

    ' A custom View Schema class
    Public Class BookListViewSchema
        Implements IDataSourceViewSchema

        Public Sub New()
        End Sub

        ' The name of this View Schema
        Public ReadOnly Property Name() As String Implements IDataSourceViewSchema.Name
            Get
                Return "BookList"
            End Get
        End Property

        ' Build a Field Schema array
        Public Function GetFields() As IDataSourceFieldSchema() Implements IDataSourceViewSchema.GetFields
            Dim fields(1) As IDataSourceFieldSchema
            fields(0) = New CustomIDFieldSchema()
            fields(1) = New CustomTitleFieldSchema()
            Return fields
        End Function
        ' There are no child views, so return Nothing
        Public Function GetChildren() As IDataSourceViewSchema() Implements IDataSourceViewSchema.GetChildren
            Return Nothing
        End Function
    End Class

    ' A custom Field Schema class for ID
    Public Class CustomIDFieldSchema
        Implements IDataSourceFieldSchema

        Public Sub New()
        End Sub

        ' Name is ID
        Public ReadOnly Property Name() As String Implements IDataSourceFieldSchema.Name
            Get
                Return "ID"
            End Get
        End Property
        ' Data type is string
        Public ReadOnly Property DataType() As Type Implements IDataSourceFieldSchema.DataType
            Get
                Return GetType(String)
            End Get
        End Property
        ' This is not an Identity field
        Public ReadOnly Property Identity() As Boolean Implements IDataSourceFieldSchema.Identity
            Get
                Return False
            End Get
        End Property
        ' This field is read only
        Public ReadOnly Property IsReadOnly() As Boolean Implements IDataSourceFieldSchema.IsReadOnly
            Get
                Return True
            End Get
        End Property
        ' This field is unique
        Public ReadOnly Property IsUnique() As Boolean Implements IDataSourceFieldSchema.IsUnique
            Get
                Return True
            End Get
        End Property
        ' This field can't be longer than 20
        Public ReadOnly Property Length() As Integer Implements IDataSourceFieldSchema.Length
            Get
                Return 20
            End Get
        End Property
        ' This field can't be null
        Public ReadOnly Property Nullable() As Boolean Implements IDataSourceFieldSchema.Nullable
            Get
                Return False
            End Get
        End Property
        ' This is a Primary Key
        Public ReadOnly Property PrimaryKey() As Boolean Implements IDataSourceFieldSchema.PrimaryKey
            Get
                Return True
            End Get
        End Property

        ' These properties do not apply
        Public ReadOnly Property Precision() As Integer Implements IDataSourceFieldSchema.Precision
            Get
                Return -1
            End Get
        End Property
        Public ReadOnly Property Scale() As Integer Implements IDataSourceFieldSchema.Scale
            Get
                Return -1
            End Get
        End Property
    End Class

    ' A custom Field Schema class for Title
    Public Class CustomTitleFieldSchema
        Implements IDataSourceFieldSchema

        Public Sub New()
        End Sub

        ' Name is Title
        Public ReadOnly Property Name() As String Implements IDataSourceFieldSchema.Name
            Get
                Return "Title"
            End Get
        End Property
        ' Type is string
        Public ReadOnly Property DataType() As Type Implements IDataSourceFieldSchema.DataType
            Get
                Return GetType(String)
            End Get
        End Property
        ' This is not an Identity field
        Public ReadOnly Property Identity() As Boolean Implements IDataSourceFieldSchema.Identity
            Get
                Return False
            End Get
        End Property
        ' This field is not read only
        Public ReadOnly Property IsReadOnly() As Boolean Implements IDataSourceFieldSchema.IsReadOnly
            Get
                Return False
            End Get
        End Property
        ' This field is not unique
        Public ReadOnly Property IsUnique() As Boolean Implements IDataSourceFieldSchema.IsUnique
            Get
                Return False
            End Get
        End Property
        ' This field can't be longer than 100
        Public ReadOnly Property Length() As Integer Implements IDataSourceFieldSchema.Length
            Get
                Return 100
            End Get
        End Property
        ' This field can't be null
        Public ReadOnly Property Nullable() As Boolean Implements IDataSourceFieldSchema.Nullable
            Get
                Return False
            End Get
        End Property
        ' This is not the Primary Key
        Public ReadOnly Property PrimaryKey() As Boolean Implements IDataSourceFieldSchema.PrimaryKey
            Get
                Return False
            End Get
        End Property

        ' These properties do not apply
        Public ReadOnly Property Precision() As Integer Implements IDataSourceFieldSchema.Precision
            Get
                Return -1
            End Get
        End Property
        Public ReadOnly Property Scale() As Integer Implements IDataSourceFieldSchema.Scale
            Get
                Return -1
            End Get
        End Property
    End Class

End Namespace

<%@ Page Language="C#" %>
<%@ Register TagPrefix="aspSample" Namespace="ASPNet.Design.Samples_CS" %>

<!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" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <aspSample:CustomDataSource ID="CustomDS1" 
        runat="server"></aspSample:CustomDataSource>
    <asp:GridView ID="GridView1" runat="server"></asp:GridView>
    
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>
<%@ Register TagPrefix="aspSample" 
    Namespace="ASPNet.Design.Samples_VB" %>

<!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" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <aspSample:CustomDataSource runat="server" 
        ID="CustomDS1"></aspSample:CustomDataSource>
    <asp:GridView ID="GridView1" runat="server"></asp:GridView>
    
    </div>
    </form>
</body>
</html>

Commenti

La DataSourceDesigner classe è la classe di base per le finestre di progettazione origine dati, ad esempio le SqlDataSourceDesignerclassi , AccessDataSourceDesignere ObjectDataSourceDesigner . Se si crea un nuovo controllo origine dati, è anche possibile creare una finestra di progettazione di controlli personalizzata per il DataSourceDesigner controllo e derivarla dalla classe.

La DataSourceDesigner classe include due metodi di evento: i OnDataSourceChanged metodi e OnSchemaRefreshed . Entrambi questi eventi possono essere disabilitati temporaneamente con il SuppressDataSourceEvents metodo, che imposta la SuppressingDataSourceEvents proprietà. I metodi evento possono essere abilitati di nuovo con il ResumeDataSourceEvents metodo .

Esistono due metodi statici che è possibile usare per valutare l'equivalenza di schemi o viste senza creare un'istanza della classe:

• Il SchemasEquivalent metodo confronta due schemi.

• Il ViewSchemasEquivalent metodo confronta gli schemi di due visualizzazioni.

Note per gli eredi

Per fornire comandi per il menu elenco azioni in fase di progettazione in una classe derivata, è necessario eseguire l'override della ActionLists proprietà per restituire un oggetto personalizzato con elementi personalizzati DesignerActionListCollection derivati dall'oggetto DesignerActionList .

Costruttori

Proprietà

Metodi

Eventi

Implementazioni dell'interfaccia esplicita

Si applica a

Vedi anche

• DataSourceControl
• Estensione del supporto in fase di progettazione
• Procedura: estendere l'aspetto e il comportamento di controlli in modalità progettazione