通过

HttpCapabilitiesBase.SupportsUncheck 属性

  • 参考

定义

命名空间:
System.Web.Configuration
程序集:
System.Web.dll

获取一个值，该值指示是否在回发数据中反映对选中的 HTML <input type=checkbox> 元素的取消选中操作。

public:
 virtual property bool SupportsUncheck { bool get(); };
public virtual bool SupportsUncheck { get; }
member this.SupportsUncheck : bool
Public Overridable ReadOnly Property SupportsUncheck As Boolean

属性值

Boolean

如果在回发数据中反映对选中的 HTML true 元素的取消选中操作，则为 <input type=checkbox>；否则为 false。 默认值为 true。

示例

下面的代码示例演示如何确定检查的 HTML <input type=checkbox> 元素的清除是否反映在回发数据中。

<%@ 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">
    void Page_Load(Object Sender, EventArgs e)
    {
        CheckBrowserCaps();
    }

    void CheckBrowserCaps()
    {
        String labelText = "";
        System.Web.HttpBrowserCapabilities myBrowserCaps = Request.Browser;
        if (((System.Web.Configuration.HttpCapabilitiesBase)myBrowserCaps).SupportsUncheck)
        {
            labelText = "Browser reflects the unchecking of a checked HTML CHECKBOX element in postback data.";
        }
        else
        {
            labelText = "Browser does not reflect the unchecking of a checked HTML CHECKBOX element in postback data.";
        }

        Label1.Text = labelText;
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Browser Capabilities Sample</title>
</head>
<body>
    <form runat="server" id="form1">
        <div>
            Browser Capabilities:
            <p/><asp:Label ID="Label1" Runat="server" />
        </div>
    </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 Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
        CheckBrowserCaps()
    End Sub

    Function CheckBrowserCaps()

        Dim labelText As String = ""
        Dim myBrowserCaps As System.Web.HttpBrowserCapabilities = Request.Browser
        If (CType(myBrowserCaps, System.Web.Configuration.HttpCapabilitiesBase)).SupportsUncheck Then
            labelText = "Browser reflects the unchecking of a checked HTML CHECKBOX element in postback data."
        Else
            labelText = "Browser does not reflect the unchecking of a checked HTML CHECKBOX element in postback data."
        End If

        Label1.Text = labelText

    End Function 'CheckBrowserCaps
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Browser Capabilities Sample</title>
</head>
<body>
    <form runat="server" id="form1">
        <div>
            Browser Capabilities:
            <p/><asp:Label ID="Label1" Runat="server" />
        </div>
    </form>
</body>
</html>

注解

如果false，HTML 元素的属性<input type=checkbox>的值checked将从回发数据中省略。

适用于