BaseDataList.IsBindableType-Methode
Bestimmt, ob der angegebene Datentyp an ein von der BaseDataList-Klasse abgeleitetes Listensteuerelement gebunden werden kann.
Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)
Syntax
'Declaration
Public Shared Function IsBindableType ( _
type As Type _
) As Boolean
'Usage
Dim type As Type
Dim returnValue As Boolean
returnValue = BaseDataList.IsBindableType(type)
public static bool IsBindableType (
Type type
)
public:
static bool IsBindableType (
Type^ type
)
public static boolean IsBindableType (
Type type
)
public static function IsBindableType (
type : Type
) : boolean
Parameter
- type
Ein System.Type, der den zu testenden Datentyp enthält.
Rückgabewert
true, wenn der angegebene Datentyp an ein von der BaseDataList-Klasse abgeleitetes Listensteuerelement gebunden werden kann, andernfalls false.
Hinweise
Mit der statischen IsBindableType-Methode können Sie bestimmen, ob der angegebene Datentyp an ein Listensteuerelement gebunden werden kann, das von der BaseDataList-Klasse erbt. Die unterstützten Datentypen sind System.Boolean, System.Byte, System.SByte, System.Int16, System.UInt16, System.Int32, System.UInt32, System.Int64, System.UInt64, System.Char, System.Double, System.Single, System.DateTime, System.Decimal und System.String.
Beispiel
Im folgenden Codebeispiel wird veranschaulicht, wie mithilfe der IsBindableType-Eigenschaft bestimmt wird, ob Werte eines bestimmten Datentyps an ein DataGrid-Steuerelement gebunden werden können.
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<html>
<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)
' Load sample data only once when the page is first loaded.
If Not IsPostBack Then
' Retrieve sample data.
Dim Source As DataView = CreateDataSource()
' Bind the data source to the DataGrid control if each column in
' the data source contains a data type that is compatible with the
' DataGrid; Otherwise, display an error message.
If ValidateSourceTypes(Source) Then
ItemsGrid.DataSource = Source
ItemsGrid.DataBind()
Else
Message.Text = "The data source is not compatible with the DataGrid control."
End If
End If
End Sub
Function ValidateSourceTypes(Source As DataView) As Boolean
' Test the data type of each column in the data source to make
' sure it is compatible with the DataGrid control.
' Initialize the success flag to True.
Dim Success As Boolean = True
' Iterate through each column of the data source and test the
' data type for compatibility with the DataGrid control.
Dim column As DataColumn
For Each column In Source.Table.Columns
If Not BaseDataList.IsBindableType(column.DataType) Then
Success = False
End If
Next
Return Success
End Function
</script>
<body>
<form runat=server>
<h3>BaseDataList IsBindableType Example</h3>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
GridLines="Both"
AutoGenerateColumns="true"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
</asp:DataGrid>
<br><br>
<asp:Label id="Message"
runat="server"/>
</form>
</body>
</html>
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<html>
<script runat="server">
DataView 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)
{
// Load sample data only once when the page is first loaded.
if (!IsPostBack)
{
// Retrieve sample data.
DataView Source = CreateDataSource();
// Bind the data source to the DataGrid control if each column
// in the data source contains a data type that is compatible
// with the DataGrid; otherwise, display an error message.
if(ValidateSourceTypes(Source))
{
ItemsGrid.DataSource = Source;
ItemsGrid.DataBind();
}
else
{
Message.Text = "The data source is not compatible with the DataGrid control.";
}
}
}
bool ValidateSourceTypes(DataView Source)
{
// Test the data type of each column in the data source to make
// sure it is compatible with the DataGrid control.
// Initialize the success flag to true.
bool Success = true;
// Iterate through each column of the data source and test the
// data type for compatibility with the DataGrid control.
foreach(DataColumn column in Source.Table.Columns)
{
if(!BaseDataList.IsBindableType(column.DataType))
{
Success = false;
}
}
return Success;
}
</script>
<body>
<form runat=server>
<h3>BaseDataList IsBindableType Example</h3>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
GridLines="Both"
AutoGenerateColumns="true"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
</asp:DataGrid>
<br><br>
<asp:Label id="Message"
runat="server"/>
</form>
</body>
</html>
Plattformen
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
Siehe auch
Referenz
BaseDataList-Klasse
BaseDataList-Member
System.Web.UI.WebControls-Namespace
System.Type
System.DateTime
System.Decimal
Type.IsPrimitive
System.Boolean
System.Byte
System.SByte
System.Int16
System.UInt16
System.Int32
System.UInt32
System.Int64
System.UInt64
System.Char
System.Double
System.Single
System.DateTime
System.Decimal
System.String