首先，递归循环浏览页面上的控件。使用以下助手类：
using System.Web.UI;
public class ReflectionHelper
{
/// <summary>
/// Check Control for match on ID and recursively check all Children for match on ID.
/// </summary>
/// <param name="ParentControl"></param>
/// <param name="ControlId"></param>
/// <returns>Control if found, null if not found</returns>
/// /// <remarks>Jason Williams | 9/7/2014 | webprogrammerguy.com</remarks>
public static Control FindControlRecursive(Control ParentControl, string ControlId)
{
if (ParentControl.ID == ControlId) {
return ParentControl;
}
foreach (Control Ctl in ParentControl.Controls) {
Control FoundCtl = FindControlRecursive(Ctl, ControlId);
if ((FoundCtl != null)) {
return FoundCtl;
}
}
return null;
}
/// <summary>
/// Check Control for match on ID and recursively check all Children for match on ID. Attempt to Invoke() Control method.
/// </summary>
/// <param name="ParentControl"></param>
/// <param name="ControlId"></param>
/// <param name="MethodName"></param>
/// <param name="parameters"></param>
/// <returns>bool true if executed, bool false if error or not executed</returns>
/// /// <remarks>Jason Williams | 9/7/2014 | webprogrammerguy.com</remarks>
public static bool FindControlRecursiveAndInvokeMethod(Control ParentControl, string ControlId, string MethodName, object[] parameters)
{
var ctrl = FindControlRecursive(ParentControl, ControlId);
if (ctrl != null)
{
try
{
MethodInfo[] ctrlMethods = ctrl.GetType().GetMethods();
foreach (MethodInfo method in ctrlMethods)
{
if (method.Name == MethodName)
{
method.Invoke(ctrl, parameters);
return true;
}
}
//return false;
}
catch (System.Exception)
{
//return false;
}
}
else
{
//return false;
}
return false;
}
/// <summary>
/// Check Control for match on ID and recursively check all Children for match on ID. Attempt to set SetValue() on Control property.
/// </summary>
/// <param name="ParentControl"></param>
/// <param name="ControlId"></param>
/// <param name="PropertyName"></param>
/// <param name="value"></param>
/// <returns>bool true if executed, bool false if error or not executed</returns>
/// /// <remarks>Jason Williams | 9/7/2014 | webprogrammerguy.com</remarks>
public static bool FindControlRecursiveAndSetPropertyValue(Control ParentControl, string ControlId, string PropertyName, string value)
{
var ctrl = FindControlRecursive(ParentControl, ControlId);
if (ctrl != null)
{
try
{
PropertyInfo[] ctrlProperties = ctrl.GetType().GetProperties();
foreach (PropertyInfo property in ctrlProperties)
{
if (property.Name == PropertyName)
{
property.SetValue(ctrl, value, new object[0]);
return true;
}
}
//return false;
}
catch (System.Exception)
{
//return false;
}
}
else
{
//return false;
}
return false;
}
/// <summary>
/// Check Control for match on ID and recursively check all Children for match on ID. Attempt to set SetValue() on Control property.
/// </summary>
/// <param name="ParentControl"></param>
/// <param name="ControlId"></param>
/// <param name="PropertyName"></param>
/// <param name="value"></param>
/// <returns>bool true if executed, bool false if error or not executed</returns>
/// <remarks>Jason Williams | 9/7/2014 | webprogrammerguy.com</remarks>
public static bool FindControlRecursiveAndSetPropertyValue(Control ParentControl, string ControlId, string PropertyName, int value)
{
var ctrl = FindControlRecursive(ParentControl, ControlId);
if (ctrl != null)
{
try
{
PropertyInfo[] ctrlProperties = ctrl.GetType().GetProperties();
foreach (PropertyInfo property in ctrlProperties)
{
if (property.Name == PropertyName)
{
property.SetValue(ctrl, value, new object[0]);
return true;
}
}
//return false;
}
catch (System.Exception)
{
//return false;
}
}
else
{
//return false;
}
return false;
}
}
其次，使用类获取Control Ref：
Control ctrlActionMemberDropdown = ReflectionHelper.FindControlRecursive(this.Page, "action_member_dropdown");
第三，将行插入到 DropDownList 控件中：
ctrlActionMemberDropdown.Items.Insert(0, "<-- Select -->");
谢谢，