HtmlInputImage.CausesValidation 属性

定义

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。Gets or sets a value indicating whether validation is performed when the HtmlInputImage control is clicked.

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, set
Public Property CausesValidation As Boolean
Public Overridable Property CausesValidation As Boolean

属性值

Boolean

如果在单击 HtmlInputImage 控件后执行验证,则为 true;否则为 falsetrue if validation is performed when the HtmlInputImage control is clicked; otherwise, false. 默认值是 trueThe default value is true.

示例

下面的代码示例演示如何使用 CausesValidation 属性来防止页验证发生。The following code example demonstrates how to use the CausesValidation property to prevent page validation from occurring. 请注意该 Validate 方法独立激活每个验证控件的方式。Notice how the Validate method activates each validation control independently.


<%@ 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,在单击控件时将执行页验证 HtmlInputImageBy default, page validation is performed when an HtmlInputImage control is clicked. 页验证确定与页上的验证控件关联的输入控件是否全部通过验证控件指定的验证规则。Page validation determines whether the input controls associated with a validation control on the page all pass the validation rules specified by the validation control.

HtmlInputImage使用属性单击控件时,可以指定或确定是否在客户端和服务器上执行验证 CausesValidationYou can specify or determine whether validation is performed on both the client and the server when an HtmlInputImage control is clicked by using the CausesValidation property. 若要防止执行验证,请将 CausesValidation 属性设置为 falseTo prevent validation from being performed, set the CausesValidation property to false.

此属性通常用于事件的事件处理程序中 ServerClick ,以防止在单击 "取消" 或 "重置" 按钮时进行页验证。This property is commonly used in the event handler for the ServerClick event to prevent page validation from occurring when a Cancel or Reset button is clicked.

适用于

另请参阅