SqlDataSource.Delete Method
Definition
Important
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Performs a delete operation using the DeleteCommand SQL string and any parameters that are in the DeleteParameters collection.
public:
int Delete();public int Delete ();member this.Delete : unit -> intPublic Function Delete () As IntegerReturns
A value that represents the number of rows deleted from the underlying database.
Exceptions
The SqlDataSource cannot establish a connection with the underlying data source.
Examples
The following code example demonstrates how to set the DeleteCommand text to delete an order from the Northwind database. Initially, data is retrieved from the Orders table and displayed in a DropDownList control. You must explicitly declare the DeleteParameters property and call the Delete method when using data-bound controls, such as the DropDownList (unlike other controls, such as GridView and DetailsView, which automatically populate the parameters and call the Delete method on a data source control). In this example, the OnClick event is delegated to the private OnDelete event handler, which explicitly calls the Delete method of the SqlDataSource control.
<%@Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
private void OnDelete(Object sender, EventArgs e) {
SqlDataSource1.Delete();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
SelectCommand="SELECT OrderID FROM Orders"
DeleteCommand="DELETE FROM [Order Details] WHERE OrderID=@OrderID;DELETE FROM Orders WHERE OrderID=@OrderID;">
<DeleteParameters>
<asp:ControlParameter Name="OrderID" ControlId="DropDownList1" PropertyName="SelectedValue" />
</DeleteParameters>
</asp:SqlDataSource>
<asp:DropDownList
id="DropDownList1"
runat="server"
DataTextField="OrderID"
DataValueField="OrderID"
DataSourceID="SqlDataSource1">
</asp:DropDownList>
<asp:Button
id="Button1"
runat="server"
Text="Delete Order"
OnClick="OnDelete">
</asp:Button>
</form>
</body>
</html>
<%@Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub On_Delete(ByVal sender As Object, ByVal e As EventArgs)
SqlDataSource1.Delete()
End Sub 'On_Delete
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
SelectCommand="SELECT OrderID FROM Orders"
DeleteCommand="DELETE FROM [Order Details] WHERE OrderID=@OrderID;DELETE FROM Orders WHERE OrderID=@OrderID;">
<DeleteParameters>
<asp:ControlParameter Name="OrderID" ControlId="DropDownList1" PropertyName="SelectedValue" />
</DeleteParameters>
</asp:SqlDataSource>
<asp:DropDownList
id="DropDownList1"
runat="server"
DataTextField="OrderID"
DataValueField="OrderID"
DataSourceID="SqlDataSource1">
</asp:DropDownList>
<asp:Button
id="Button1"
runat="server"
Text="Delete Order"
OnClick="On_Delete">
</asp:Button>
</form>
</body>
</html>
Remarks
Before the delete operation is performed, the OnDeleting method is called to raise the Deleting event. You can handle this event to examine the values of the parameters and to perform any preprocessing before a delete operation.
After the operation completes, the OnDeleted method is called to raise the Deleted event. You can handle this event to examine any return values and error codes and to perform any post-processing.
The Delete method is provided for programmatic access to the Delete method. If the SqlDataSource control is associated with a data-bound control, the data-bound control automatically calls the Delete method.
The Delete method delegates to the Delete method of the SqlDataSourceView object that is associated with the SqlDataSource control. To perform the operation, the SqlDataSourceView builds a DbCommand object using the DeleteCommand text and any associated DeleteParameters values, and then executes the DbCommand against the underlying database.
