NullReferenceException while showing /hiding a DIV

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<div style="margin-top:2%; width: 100%; background: #FFBF02;">
      <div id="blocks" runat ="server"  >
          <span id="snbox1" onclick="return ShowClick('Company');" class="span-box1"style="position: relative; cursor: pointer;">
                 <span id="snplaceholderFirma"  class="image-placeholderCompany"> <img id="img1" src="Images/images.png" style="height: 90px;" /> </span>
                 <span id="snFirma" style="background-color: #808080" class="text-content">Firma</span>
                 <span style="clear: both;"></span>
             </span>

            <span id="snbox2" onclick="" class="span-box2" style="position: relative; cursor: pointer;">
                <span id="snplaceholderBenutzer" class="image-placeholderUser"> <img id="img2" src="Images/images.png" style="height: 90px" /> </span>
                 <span id="snBenutzer" style="background-color: #808080" class="text-content"></span>
                 <span style="clear: both;"></span>
            </span>

            <span id="snbox3" onclick="" class="span-box3" style="position: relative; cursor: pointer;">
                <span id="snplaceholderFirmaMitarbeiter" class="image-placeholderCompanyEmployee"> <img id="img3" src="Images/images.png" style="height: 90px" /> </span>
                <span id="snFirmaMitarbeiter" style="background-color: #808080" class="text-content"> </span>
                <span style="clear: both;"></span>
            </span>
      </div>
    <div id="blocksTile"  runat ="server">
             <span id="snboxs1" onclick="" class="span-box1"style="position: relative; cursor: pointer;">
                 <span id="snplaceholderFirmas"  class="image-placeholderCompany"> <img id="imgs1" src="Images/images.png" style="height: 90px;" /> </span>
                 <span id="snFirmas" style="background-color: #808080" class="text-content">Test 1</span>
                 <span style="clear: both;"></span>
             </span>

            <span id="snboxs2" onclick="" class="span-box2" style="position: relative; cursor: pointer;">
                <span id="snplaceholderBenutzers" class="image-placeholderUser"> <img id="imgs2" src="Images/images.png" style="height: 90px" /> </span>
                 <span id="snBenutzers" style="background-color: #808080" class="text-content">Test 2</span>
                 <span style="clear: both;"></span>
            </span>

            <span id="snboxs3" onclick="" class="span-box3" style="position: relative; cursor: pointer;">
                <span id="snplaceholderFirmaMitarbeiters" class="image-placeholderCompanyEmployee"> <img id="imgs3" src="Images/images.png" style="height: 90px" /> </span>
                <span id="snFirmaMitarbeiters" style="background-color: #808080" class="text-content">Test 3</span>
                <span style="clear: both;"></span>
            </span>
      </div>

  </div>

This is the HTML Code. Based on a condition I want to hide/show the div.

C#

if (Convert.ToInt32(GlobalValues[0]) == 1)
                {
                   blocks.Visible = true;
                   blocksTile.Visible = false ;

                }
                else if (Convert.ToInt32(GlobalValues[0]) == 2)
                {
                    blocksTile.Visible = true;
                    blocks.Visible = false;
                }
                else
                {
                    blocks.Visible = true;
                    blocksTile.Visible = false;
                }

But it results NULL EXCEPTION ERROR... Please help me to solve this

Posted 12-Jan-15 20:12pm

jithesh a

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Comments

m-shraddha 13-Jan-15 2:50am

You might be getting value of GlobalValues[0] as a null...Therefore its throwing an exception because it cannot convert null value to an integer. You can check the value by debugging your code. :)

jithesh a 13-Jan-15 2:55am

Ho..Never ...Its getting an integer value. Error is getting on div ;)

Sanket Saxena 13-Jan-15 7:42am

On which event you are writing your code behind code?

2 solutions

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Amresh Bahadur Singh · Answer 1 · 2015-01-13T01:36:00

Solution 1

debugging your code. And use HtmlGenericControl for HTML Control .
for ex.

HtmlGenericControl div = (HtmlGenericControl)this.FindControl("div1");

Posted 13-Jan-15 1:36am

Amresh Bahadur Singh

Sanket Saxena · Answer 2 · 2015-01-13T01:46:00

Solution 2

I found that you have this div inside another div that is not runat="Server". So make the parent also runat="server" and try.

ASP.NET

<div runat="server" style="margin-top:2%; width: 100%; background: #FFBF02;">
      <div id="blocks" runat="server"></div>
</div>

Hope it helps :)

Posted 13-Jan-15 1:46am

Sanket Saxena