HtmlInputImage.CausesValidation 属性
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
获取或设置一个值，该值指示在单击 HtmlInputImage 控件时是否执行验证。
public:
property bool CausesValidation { bool get(); void set(bool value); };public:
virtual property bool CausesValidation { bool get(); void set(bool value); };public bool CausesValidation { get; set; }public virtual bool CausesValidation { get; set; }member this.CausesValidation : bool with get, setPublic Property CausesValidation As BooleanPublic Overridable Property CausesValidation As Boolean属性值
如果在单击 HtmlInputImage 控件后执行验证，则为 true；否则为 false。 默认值是 true。
示例
下面的代码示例演示如何使用 CausesValidation 属性来防止页面验证发生。 请注意 方法 Validate 如何独立激活每个验证控件。
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void SubmitButton_Click(Object sender, ImageClickEventArgs e)
{
// Determine which button was clicked.
switch (((HtmlInputImage)sender).ID)
{
case "CityQueryButton":
// Validate only the controls used for the city query.
CityReqValidator.Validate();
// Take the appropriate action if the controls pass validation.
if (CityReqValidator.IsValid)
{
Message.InnerHtml = "You have chosen to run a query for the following city: " +
CityTextBox.Value;
}
break;
case "StateQueryButton":
// Validate only the controls used for the state query.
StateReqValidator.Validate();
// Take the appropriate action if the controls pass validation.
if (StateReqValidator.IsValid)
{
Message.InnerHtml = "You have chosen to run a query for the following state: " +
StateTextBox.Value;
}
break;
default:
// If the button clicked is not recognized, erase the message on the page.
Message.InnerHtml = "";
break;
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title> HtmlInputImage CausesValidation Example </title>
</head>
<body>
<form id="form1" runat="server">
<h3> HtmlInputImage CausesValidation Example </h3>
<table border="1" cellpadding="10">
<tr>
<td>
<b>Enter city to query.</b> <br />
<input id="CityTextBox"
type="Text"
runat="server"/>
<asp:RequiredFieldValidator
ID="CityReqValidator"
ControlToValidate="CityTextBox"
ErrorMessage="<br />Please enter a city."
Display="Dynamic"
EnableClientScript="False"
runat="server"/>
</td>
<td valign="bottom">
<input id="CityQueryButton"
alt="City Submit button"
type="Image"
src="image.jpg"
causesvalidation="False"
onserverclick="SubmitButton_Click"
runat="server"/>
</td>
</tr>
<tr>
<td>
<b>Enter state to query.</b> <br />
<input id="StateTextBox"
type="Text"
runat="server"/>
<asp:RequiredFieldValidator ID="StateReqValidator"
ControlToValidate="StateTextBox"
ErrorMessage="<br />Please enter a state."
Display="Dynamic"
EnableClientScript="False"
runat="server"/>
</td>
<td valign="bottom">
<input id="StateQueryButton"
alt="State Submit button"
type="Image"
src="image.jpg"
causesvalidation="False"
onserverclick="SubmitButton_Click"
runat="server"/>
</td>
</tr>
</table>
<br /><br />
<span id="Message"
runat="Server"/>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub SubmitButton_Click(ByVal sender As Object, ByVal e As ImageClickEventArgs)
' Determine which button was clicked.
Select Case (CType(sender, HtmlInputImage)).ID
Case "CityQueryButton"
' Validate only the controls used for the city query.
CityReqValidator.Validate()
' Take the appropriate action if the controls pass validation.
If CityReqValidator.IsValid Then
Message.InnerHtml = "You have chosen to run a query for the following city: " & _
CityTextBox.Value
End If
Case "StateQueryButton"
' Validate only the controls used for the state query.
StateReqValidator.Validate()
' Take the appropriate action if the controls pass validation.
If StateReqValidator.IsValid Then
Message.InnerHtml = "You have chosen to run a query for the following state: " & _
StateTextBox.Value
End If
Case Else
' If the button clicked isn not recognized, erase the message on the page.
Message.InnerHtml = ""
End Select
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title> HtmlInputImage CausesValidation Example </title>
</head>
<body>
<form id="form1" runat="server">
<h3> HtmlInputImage CausesValidation Example </h3>
<table border="1" cellpadding="10">
<tr>
<td>
<b>Enter city to query.</b> <br />
<input id="CityTextBox"
type="Text"
runat="server"/>
<asp:RequiredFieldValidator ID="CityReqValidator"
ControlToValidate="CityTextBox"
ErrorMessage="<br />Please enter a city."
Display="Dynamic"
EnableClientScript="False"
runat="server"/>
</td>
<td valign="bottom">
<input id="CityQueryButton"
alt="City Submit button"
type="Image"
src="SubmitImage.jpg"
causesvalidation="False"
onserverclick="SubmitButton_Click"
runat="server"/>
</td>
</tr>
<tr>
<td>
<b>Enter state to query.</b> <br />
<input id="StateTextBox"
type="Text"
runat="server"/>
<asp:RequiredFieldValidator ID="StateReqValidator"
ControlToValidate="StateTextBox"
ErrorMessage="<br />Please enter a state."
Display="Dynamic"
EnableClientScript="False"
runat="server"/>
</td>
<td valign="bottom">
<input id="StateQueryButton"
alt="State Submit button"
type="Image"
src="SubmitImage.jpg"
causesvalidation="False"
onserverclick="SubmitButton_Click"
runat="server"/>
</td>
</tr>
</table>
<br /><br />
<span id="Message"
runat="Server"/>
</form>
</body>
</html>
注解
默认情况下，在单击控件时 HtmlInputImage 执行页面验证。 页面验证确定与页面上的验证控件关联的输入控件是否都通过验证控件指定的验证规则。
使用 属性单击CausesValidation控件时HtmlInputImage，可以指定或确定是否在客户端和服务器上执行验证。 若要防止执行验证，请将 CausesValidation 属性设置为 false。
此属性通常用于事件的事件处理程序 ServerClick 中，以防止在单击“取消”或“重置”按钮时发生页面验证。
