validate field if checkbox.checked 2

[devRyan]

Hi all,

I was wondering how to require a text field on the condition that a checkbox is checked.

I have a text field that collects a completion date with a related checkbox that denotes isComplete. I want to set a requiredField validator on the text field.

I've added a required field validator to the text field and set it to enabled=false, and in the code behind when I confirm that the check box is checked, I set the requiredField validator to enabled=true, then call the validate function for the validator, like so:

if (checkbox.chacked)
{
this.reqValDateCompleted = true;
this.reqValDateCompleted.Validate();
}

but nothing happens, which makes me think I'm using the wrong methods for doing this.

Can someone point me in the right direction, please?

 

[TipGiver]

Set the check box's autopostback to true.
Write code in the checkbox default event handler:

((RequiredFieldValidator)this.findcontrol("reqValDateCompleted")).Enabled = CheckBoxName.Checked();


I have tested it in VB.. and i hope my conversion is correct and work for c#.

 

[devRyan]

Thanks for responding.

When I run this I get a NullReferenceException was unhandled by user code: Object reference not set to an instance of an object; on the line:

((RequiredFieldValidator)this.FindControl("reqValDateCompleted")).Enabled = isResolved.Checked;

The field names are correct.

 

[devRyan]

The default event handler is as follow:

protected void chkIsResolved_CheckedChanged(object sender, EventArgs e)
{
((RequiredFieldValidator)this.FindControl("reqValDateCompleted")).Enabled = chkIsResolved.Checked;
}

 

[TipGiver]

private void isResolved_CheckedChanged(object sender, System.EventArgs e)
{
((RequiredFieldValidator)this.FindControl("reqValDateCompleted")).Enabled = isResolved.Checked;
}


Works for me.
Make sure to set the autopostback of the isResolved.

 

[devRyan]

I've got autopostback set to true. I tried using private instead of protected in the declaration, but I get a compilation error saying that the method can't be reached due to its protection level.

 

[TipGiver]

Please write the whole compilation error message you get.

 

[devRyan]

Error 1 'EditBugs.chkIsResolved_CheckedChanged(object, System.EventArgs)' is inaccessible due to its protection level C:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\WebSites\BugTracker\editBug.aspx 74

 

[devRyan]

I'm still having problems with this. Any other insight?

 

[TipGiver]

I cant think of something helpful right now. I have not come across this kind of error.
I'll have this in mind.
Sorry

(This works for me fine. Did you start this project in these days? I mean, can you upload it somewhere so (others and) i can download it and have a closer look?)

Errr, is this prohibited by the tektips forums ?

 

[devRyan]

I'll see if I can

 

[ca8msm]

It's not prohibited but as long as you paste the relevant code on here so that others can see it will be fine.


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[TipGiver]

You are right.
I don't know what part of code to ask devRyan to paste.

 

[devRyan]

Here is the frontside

<tr>
    <td class="fieldName">
      Date Completed:
    </td>
    <td>
      <asp:Textbox ID="txtDateCompleted" runat="server" />
      <asp:CompareValidator ID="comValDateCompleted" runat="server" Display="Dynamic"
      ControlToValidate="txtDateCompleted" SetFocusOnError="true" Operator="DataTypeCheck" Type="Date"
      ErrorMessage="Please enter a valid date for the date completed">*</asp:CompareValidator>
      <asp:RequiredFieldValidator ID="reqValDateCompleted" runat="server" Enabled="false" Display="Dynamic"
      ErrorMessage="Please enter a completion date." SetFocusOnError="true" ControlToValidate="txtDateCompleted"
      >*</asp:RequiredFieldValidator>
      <br />
      Is Resolved:&nbsp;
      <asp:CheckBox ID="chkIsResolved" runat="server" AutoPostBack="true" OnCheckedChanged="chkIsResolved_CheckedChanged" />      
    </td>
  </tr>

...the code behind for the check box

protected void chkIsResolved_CheckedChanged(object sender, EventArgs e)
  {
    ((RequiredFieldValidator)this.FindControl("reqValDateCompleted")).Enabled = chkIsResolved.Checked;
  }

...and the libraries included in the .cs file

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections;
using System.Text;
using System.Web;
using System.Web.Configuration;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

When I run it, I get a NullReferenceException was not handle by user code: "Object reference not set to an instance of an object."

I would really rather that it fired onSubmit, but that should be easy enough to figure out once get the OnCheckedChanged worked out.

Thanks

 

[devRyan]

I've tried to rewrite it as, but I get the same result:

 RequiredFieldValidator reqVal = new RequiredFieldValidator();
    reqVal = ((RequiredFieldValidator)this.FindControl("reqValDateCompleted"));
    reqVal.Enabled = chkIsResolved.Checked;

 

[devRyan]

I've created a brand new project and copied the code I've pasted here into it, and it runs fine. I'm digging deeper at the moment.

 

[devRyan]

Ok, I've narrowed it down a little more.

My original pages use a master page, so I took my new test project, which worked, and put it in master page format. Now I get the same error on the test project.

 

[devRyan]

Here's the full code for my test site. please tell me if you get errors from it. It worked like everyone said it was, until I put it into the masterpage format, which now throws the same error as my main project(which uses master pages).

Master page

<%@ Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "[URL unfurl="true"]http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">[/URL]

<html xmlns="[URL unfurl="true"]http://www.w3.org/1999/xhtml"[/URL] >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:contentplaceholder id="ContentPlaceHolder1" runat="server">
        </asp:contentplaceholder>
    </div>
    </form>
</body>
</html>

Default aspx

<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<table>
      <tr>
        <td class="fieldName">
          Date Completed:
        </td>
        <td>
          <asp:Textbox ID="txtDateCompleted" runat="server" />
          <asp:CompareValidator ID="comValDateCompleted" runat="server" Display="Dynamic"
          ControlToValidate="txtDateCompleted" SetFocusOnError="true" Operator="DataTypeCheck" Type="Date"
          ErrorMessage="Please enter a valid date for the date completed">*</asp:CompareValidator>
          <asp:RequiredFieldValidator ID="reqValDateCompleted" runat="server" Enabled="false" Display="Dynamic"
          ErrorMessage="Please enter a completion date." SetFocusOnError="true" ControlToValidate="txtDateCompleted"
          >*</asp:RequiredFieldValidator>
          <br />
          Is Resolved:&nbsp;
          <asp:CheckBox ID="chkIsResolved" runat="server" AutoPostBack="true" OnCheckedChanged="chkIsResolved_CheckedChanged" />      
        </td>
      </tr>
    </table>  
</asp:Content>

default aspx cs

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class _Default : System.Web.UI.Page
{
  protected void Page_Load(object sender, EventArgs e)
  {

  }

  protected void chkIsResolved_CheckedChanged(object sender, EventArgs e)
  {
    RequiredFieldValidator reqVal = new RequiredFieldValidator();
    reqVal = ((RequiredFieldValidator)this.FindControl("reqValDateCompleted"));
    reqVal.Enabled = chkIsResolved.Checked;
    reqVal.Validate();
  }
}

 

[TipGiver]

You have droped a required field validator.
Why "RequiredFieldValidator reqVal = new RequiredFieldValidator();" ?


protected void chkIsResolved_CheckedChanged(object sender, EventArgs e)
{
((RequiredFieldValidator)this.FindControl("reqValDateCompleted")).Enabled = chkIsResolved.Checked;

}


You aldeady have an instance of the validator. Do not use new. You can do it like your way, but NOT create a new one...


RequiredFieldValidator reqVal = ((RequiredFieldValidator)this.FindControl("reqValDateCompleted"));
reqVal.Enabled = chkIsResolved.Checked;

 

[devRyan]

Right, I see what you mean. I've changed it as suggested to(below), though it still throws the same error.

protected void chkIsResolved_CheckedChanged(object sender, EventArgs e)
  {
    RequiredFieldValidator reqVal = ((RequiredFieldValidator)this.FindControl("reqValDateCompleted"));
    reqVal.Enabled = chkIsResolved.Checked;
    reqVal.Validate();
  }