SqlDataSourceStatusEventArgs.Command 属性
定义
重要
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获取提交到数据库的数据库命令。
public:
property System::Data::Common::DbCommand ^ Command { System::Data::Common::DbCommand ^ get(); };public System.Data.Common.DbCommand Command { get; }member this.Command : System.Data.Common.DbCommandPublic ReadOnly Property Command As DbCommand属性值
DbCommand 对象，它表示提交到数据库的数据库命令。
示例
下面的代码示例演示如何在将控件与存储过程一起使用 SqlDataSource 时检查输出参数的值。 集合 SelectParameters 包含 用于存储过程的参数 SqlDataSource ，由将信息从 Web 窗体传递到存储过程的参数以及将信息传递回窗体的参数组成。 此代码示例是为 SqlDataSourceStatusEventArgs 类提供的一个更大示例的一部分。
<%@Page Language="C#" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
// Clicking the Submit button explicitly refreshes the data
// by calling the Select() method.
private void Submit(Object source, EventArgs e) {
SqlDataSource1.Select(DataSourceSelectArguments.Empty);
}
// This event handler is called after the Select() method is executed.
private void OnSelectedHandler(Object source, SqlDataSourceStatusEventArgs e) {
IDbCommand cmd = e.Command;
Label1.Text = "Parameter return values: ";
foreach (SqlParameter param in cmd.Parameters) {
// Extract the value of the parameter.
Label1.Text += param.ParameterName + " - " + param.Value.ToString();
}
}
</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"
datasourcemode="DataSet"
connectionstring="<%$ ConnectionStrings:MyNorthwind%>"
selectcommand="getordertotal"
onselected="OnSelectedHandler">
<selectparameters>
<asp:querystringparameter name="empId" querystringfield="empId" />
<asp:parameter name="total" type="Int32" direction="Output" defaultvalue="0" />
<asp:parameter name="_ret" type="Int32" direction="ReturnValue" defaultvalue="0" />
</selectparameters>
</asp:sqldatasource>
<!--
CREATE PROCEDURE dbo.getordertotal
@empId int,
@total int OUTPUT
as
set nocount on
select @total = count(1) from orders where employeeid=@empid;
select * from orders where employeeID = @empId ;
return (-1000);
GO
-->
<asp:gridview
id="GridView1"
runat="server"
allowpaging="True"
pagesize="5"
datasourceid="SqlDataSource1" />
<asp:button
id="Button1"
runat="server"
onclick="Submit"
text="Refresh Data" />
<asp:label id="Label1" runat="server" />
</form>
</body>
</html>
<%@Page Language="VB" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
' Clicking the Submit button explicitly refreshes the data
' by calling the Select() method.
Private Sub Submit(source As Object, e As EventArgs)
SqlDataSource1.Select(DataSourceSelectArguments.Empty)
End Sub ' Submit
' This event handler is called after the Select() method is executed.
Private Sub OnSelectedHandler(source As Object, e As SqlDataSourceStatusEventArgs)
Dim cmd As IDbCommand
cmd = e.Command
Dim param As SqlParameter
Label1.Text = "Parameter return values: "
For Each param In cmd.Parameters
' Extract the name and value of the parameter.
Label1.Text = Label1.Text & param.ParameterName & " - " & _
param.Value.ToString()
Next
End Sub ' OnSelectedHandler
</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"
datasourcemode="DataSet"
connectionstring="<%$ ConnectionStrings:MyNorthwind%>"
selectcommand="getordertotal"
onselected="OnSelectedHandler">
<selectparameters>
<asp:querystringparameter name="empId" querystringfield="empId" />
<asp:parameter name="total" type="Int32" direction="Output" defaultvalue="0" />
<asp:parameter name="_ret" type="Int32" direction="ReturnValue" defaultvalue="0" />
</selectparameters>
</asp:sqldatasource>
<!--
CREATE PROCEDURE dbo.getordertotal
@empId int,
@total int OUTPUT
as
set nocount on
select @total = count(1) from orders where employeeid=@empid;
select * from orders where employeeID = @empId ;
return (-1000);
GO
-->
<asp:gridview
id="GridView1"
runat="server"
allowpaging="True"
pagesize="5"
datasourceid="SqlDataSource1" />
<asp:button
id="Button1"
runat="server"
onclick="Submit"
text="Refresh Data" />
<asp:label id="Label1" runat="server" />
</form>
</body>
</html>
注解
可以在 控件将 SelectedUpdated、 、 Inserted或 Deleted 事件提交SqlDataSource到数据库后对其进行检查和操作DbCommand。 属性Command使你能够在通过数据库ParametersCommandText属性以及属性（表示提交到数据库的 SQL 查询、命令或存储过程名称）执行数据库操作后访问任何输出参数中的返回值和值。
任何输出参数都专门来自具有 InputOutput 对象的 属性的 或 Output 值 Direction 的参数 Parameter 。 返回值来自具有 ReturnValue 值的参数。
