RangeValidator.EvaluateIsValid Metode

Definisi

Ruang nama:
System.Web.UI.WebControls
Rakitan:
System.Web.dll

Menentukan apakah konten dalam kontrol input valid.

protected:
 override bool EvaluateIsValid();
protected override bool EvaluateIsValid();
override this.EvaluateIsValid : unit -> bool
Protected Overrides Function EvaluateIsValid () As Boolean

Mengembalikan

Boolean

true jika kontrol valid; jika tidak, false.

Contoh

Contoh kode berikut menunjukkan cara mengambil alih EvaluateIsValid metode dalam kontrol server kustom sehingga selalu memvalidasi bahwa nilai ada dan berada dalam nilai maksimum dan minimum yang ditentukan untuk RangeValidator.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ 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">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom RangeValidator - EvaluateIsValid - C# Example</title>
    <script runat="server">
      void ButtonClick(Object sender, EventArgs e)
      {
        if (Page.IsValid)
        {
          Label1.Text="Page is valid.";
        }
        else
        {
          Label1.Text="Page is not valid!!";
        }
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom RangeValidator - EvaluateIsValid - C# Example</h3>

      Enter a number from 1 to 10:<br />
      <asp:TextBox id="TextBox1" Runat="server" />

      <aspSample:CustomRangeValidatorEvaluateIsValid 
        id="RangeValidator1" 
        runat="server" 
        ControlToValidate="TextBox1" 
        MinimumValue="1" 
        MaximumValue="10" 
        Type="Integer" 
        EnableClientScript="false" 
        Text="The value must be from 1 to 10!" />
        
      <br />
      <br />
      <asp:Button id="Button1" Text="Submit" OnClick="ButtonClick" runat="server" /><br />
      <br />

      <asp:Label id="Label1" runat="server" />
    </form>
  </body>
</html>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ 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">
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom RangeValidator - EvaluateIsValid - VB.NET Example</title>
        <script runat="server">
            Sub ButtonClick(sender As Object, e As EventArgs)
                If Page.IsValid Then
                    Label1.Text="Page is valid."
                Else
                    Label1.Text="Page is not valid!"
                End If
            End Sub
        </script>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom RangeValidator - EvaluateIsValid - VB.NET Example</h3>

            Enter a number from 1 to 10:<br />
            <asp:TextBox id="TextBox1" Runat="server" />
            
            <aspSample:CustomRangeValidatorEvaluateIsValid id="RangeValidator1" runat="server" 
             ControlToValidate="TextBox1" MinimumValue="1" MaximumValue="10" Type="Integer" 
             EnableClientScript="false" Text="The value must be from 1 to 10!" /><br />
             <br />
             
            <asp:Button id="Button1" Text="Submit" OnClick="ButtonClick" runat="server" /><br />
             <br />
             
            <asp:Label id="Label1" runat="server"/>
        </form>
    </body>
</html>

using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomRangeValidatorEvaluateIsValid : System.Web.UI.WebControls.RangeValidator
  {
    protected override bool EvaluateIsValid()
    {
      // Get the value of the control to validate.
      string controlValue = GetControlValidationValue(ControlToValidate);

      // If no value was entered, show the validation error by returning false.
      if (controlValue.Trim().Length == 0) 
      {
        return false;
      }

      // Compare the ControlToValidate's value against the minimum and maximum values.
      return(Compare(controlValue, this.MinimumValue, System.Web.UI.WebControls.ValidationCompareOperator.GreaterThanEqual, this.Type) &&
        Compare(controlValue, this.MaximumValue, System.Web.UI.WebControls.ValidationCompareOperator.LessThanEqual, this.Type));
    }            
  }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public NotInheritable Class CustomRangeValidatorEvaluateIsValid
        Inherits System.Web.UI.WebControls.RangeValidator

        Protected Overrides Function EvaluateIsValid() As Boolean

            ' Get the value of the control to validate.
            Dim controlValue As String = GetControlValidationValue(ControlToValidate)

            ' If no value was entered, show the validation error by returning false.
            If controlValue.Trim().Length = 0 Then
                Return False
            End If

            ' Compare the ControlToValidate's value against the minimum and maximum values.
            Return Compare(controlValue, Me.MinimumValue, System.Web.UI.WebControls.ValidationCompareOperator.GreaterThanEqual, Me.Type) AndAlso _
                   Compare(controlValue, Me.MaximumValue, System.Web.UI.WebControls.ValidationCompareOperator.LessThanEqual, Me.Type)
        End Function
    End Class
End Namespace

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