我们不得不经常这样做,所以我做了一个我称之为 DelegateParameter 的类
using System;
using System.Collections.Generic;
using System.Text;
using System.Web.UI.WebControls;
using System.Reflection;
namespace MyControls
{
public delegate object EvaluateParameterEventHandler(object sender, EventArgs e);
public class DelegateParameter : Parameter
{
private System.Web.UI.Control _parent;
public System.Web.UI.Control Parent
{
get { return _parent; }
set { _parent = value; }
}
private event EvaluateParameterEventHandler _evaluateParameter;
public event EvaluateParameterEventHandler EvaluateParameter
{
add { _evaluateParameter += value; }
remove { _evaluateParameter -= value; }
}
protected override object Evaluate(System.Web.HttpContext context, System.Web.UI.Control control)
{
return _evaluateParameter(this, EventArgs.Empty);
}
}
}
将此类放在您的 app_code 中(如果将其放在此处,请删除命名空间)或自定义控件程序集中。在 web.config 中注册控件后,您应该可以执行此操作
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:itematConnectionString %>"
SelectCommand = "SELECT items.name, items.id FROM items INNER JOIN users_items ON items.id = users_items.id WHERE (users_items.user_id = @userId) ORDER BY users_items.date DESC">
<SelectParameters>
<asp:DelegateParameter Name="userId" DbType="Guid" OnEvaluate="GetUserID" />
</SelectParameters>
</asp:SqlDataSource>
然后在你后面的代码中实现你喜欢的 GetUserID。
protected object GetUserID(object sender, EventArgs e)
{
return userId;
}