先看下面的一个例子:
script runat = " server " language = " C# " >
void Page_Load(Object sender, EventArgs e)
{
foreach(Control c in Controls)
lblControlList.Text += c.ToString() + " - " + c.ID + "
";
}
script>
<html>
<head>
head>
<body>
<b>A List of the Controls in the
<code>Controls code> Collection b><br>
<asp:label runat="server" id="lblControlList" />
<p>
<form runat="server">
What’s your name?
<asp:textbox runat="Server" id="txtName" />
form>
body>
html>
这个例子列出页面上所有的控件,结果如下:
A List of the Controls in the
Controls
CollectionSystem.Web.UI.LiteralControl -
System.Web.UI.WebControls.Label - lblControlList
System.Web.UI.LiteralControl -
System.Web.UI.HtmlControls.HtmlForm -
System.Web.UI.ResourceBasedLiteralControl -
特别要注意的一点:以上代码没有列出ID=“txtName”的TextBox控件!因为这个TextBox控件包含在Form里面,是Form的一个子控件。而我们的代码 foreach(Control c in Controls) 只关心当前页面Controls的控件,至于子控件却未能涉及。(可以把这些控件理解成一个树状的层次关系)
页面Controls
/ | / //foreach(Control c in Controls)
控件1 控件2 控件3 // 只判断控件1、2、3属于页面Controls
/ / //而未涉及到下属子控件
子控件1 子控件2
为了真正做到遍历所有控件集,可以用递归的方法来实现:
<script runat="server" language="C#">
void IterateThroughChildren(Control parent)
{
foreach (Control c in parent.Controls)
{
lblControlList.Text += "
- " + c.ToString() + "
if (c.Controls.Count > 0) // 判断该控件是否有下属控件。
{
lblControlList.Text += "
-
"
;
IterateThroughChildren(c); //递归,访问该控件的下属控件集。
lblControlList.Text += "
}
}
}
void Page_Load(Object sender, EventArgs e)
{
lblControlList.Text += "
-
"
;
IterateThroughChildren( this );
lblControlList.Text += "
}
script>
<html>
<head>
head>
<body>
<b>A List of the Controls in the
<code>Controls code> Collection b><br>
<asp:label runat="server" id="lblControlList" />
<p>
<form runat="server">
What’s your name?
<asp:textbox runat="Server" id="txtName" />
form>
body>
html>
以上代码运行结果如下:
A List of the Controls in the Controls
Collection
- System.Web.UI.LiteralControl
- System.Web.UI.WebControls.Label
- System.Web.UI.LiteralControl
- System.Web.UI.HtmlControls.HtmlForm
- System.Web.UI.LiteralControl
- System.Web.UI.WebControls.TextBox
- System.Web.UI.LiteralControl
- System.Web.UI.ResourceBasedLiteralControl
这下TextBox控件真的露出了庐山真面目。
///
/// 控制控件是否可用
///
///
public static void EnableDisableOneControls(System.Web.UI.Control page, bool bFalg)
{
int nPageControls = page.Controls.Count;
for (int i = 0; i < nPageControls; i++)
{
foreach (System.Web.UI.Control control in page.Controls[i].Controls)
{
if (control.HasControls())
{
EnableDisableOneControls(control, bFalg);
}
else
{
if (control is TextBox)
(control as TextBox).Enabled = bFalg;
if (control is Button)
(control as Button).Enabled = bFalg;
if (control is CheckBox)
(control as CheckBox).Checked = bFalg;
if (control is DropDownList)
(control as DropDownList).Enabled = bFalg;
if (control is UserControl)
(control as UserControl).e = bFalg;
if (control is RadioButtonList)
(control as RadioButtonList).SelectedIndex = -1;
if (control is RadioButton)
(control as RadioButton).Checked = bFalg;
if (control is CheckBoxList)
{
foreach (ListItem item in (control as CheckBoxList).Items)
{
item.Selected = bFalg;
}
}
}//if..else
}//foreach
}//for
}