显示/隐藏DIV时出现NullReferenceException [英] NullReferenceException while showing /hiding a DIV
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问题描述
< div 样式 = margin-top ：2％;宽度：100％;背景：＃FFBF02; >
< ; div id < span class =code-keyword> = blocks runat = 服务器 >
< span id = snbox1 onclick = < span class =code-keyword>返回ShowClick（'Company'）; class = span-box1 style = position：relative; cursor：pointer; >
< span id = snplaceholderFirma < span class =code-attribute> class = image-placeholderCompany > < img id = img1 src = Images / images.png style = height： 90px; / > < / span >
< span < span class =code-attribute> 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 = < span class =code-keyword> position：relative; cursor：pointer; >
< span id = snplaceholderBenutzer class = image-placeholderUser > < img id = img2 src = 图像/图像.png style = height：90px / > < / span >
< ; span id < span class =code-keyword> = snBenutzer 样式 = background-color：＃808080 class = text-content > < / span >
< span style = clear：both; > < span class =code-keyword>< / span >
< / span >
< span id = snbox3 < span class =code-attribute> onclick = class = span-box3 style = position：relative; cursor：pointer; >
< span id = snplaceholderFirmaMitarbeiter class = image-placeholderCompanyEmployee > < img id = img3 src = 图像/图像.png style = height：90px / > < / span >
< span id = snFirmaMitarbeiter style = background-color：＃808080 class = text-content > < / span >
< span 样式 = clear：both; > < / span >
< / span >
< / div >
< div id = blocksTile runat = 服务器 >
< span id = snboxs1 onclick = class = span-box1 style = position：re lative; cursor：pointer; >
< span id = snplaceholderFirmas < span class =code-attribute> class = image-placeholderCompany > < img id = imgs1 src = Images / images.png style = height： 90px; / > < / span >
< span < span class =code-attribute> id = snFirmas style = background-color：＃808080 class = text-content > 测试1 < / span >
< span style = clear：both; > < / span < span class =code-keyword>>
< / span >
< span id = snboxs2 onclick = class = span -box2 style = position：relative; cursor：pointer; >
< span id = snplaceholderBenutzers class = image-placeholderUser > < img id = imgs2 src = 图像/图像.png style = height：90px / > < / span >
< ; span id < span class =code-keyword> = snBenutzers 样式 = background-color：＃808080 class = text-content > 测试2 < / span >
< span style = clear：both; > < / span >
< / span >
< span id = snboxs3 onclick = class = span-box3 style = position：相对的; cursor：pointer; >
< span id = snplaceholderFirmaMitarbeiters class = image-placeholderCompanyEmployee > < img id = imgs3 src = 图像/图像.png style = height：90px / > < / span >
< span id = snFirmaMitarbeiters style = background-color：＃808080 class = text-content > 测试3 < span class =code-keyword>< / span >
< span 样式 = clear：both; > < / span >
< / span >
< / div >
< / div >
这是HTML代码。基于我想要隐藏/显示div的条件。
如果（Convert.ToInt32（GlobalValues [ 0 ]）== 1 ）
{
blocks.Visible = true ;
blocksTile.Visible = false ;
}
else if （Convert.ToInt32（GlobalValues [ 0 ]）== 2 ）
{
blocksTile.Visible = 真;
blocks.Visible = false ;
}
else
{
blocks.Visible = true ;
blocksTile.Visible = false ;
}
但结果是NULL EXCEPTION ERROR ...请帮我解决这个问题
解决方案
< blockquote>调试代码。并使用HtmlGenericControl进行HTML控制。
for ex。
HtmlGenericControl div =（HtmlGenericControl）this.FindControl（div1）;
我发现你在另一个不是runat =Server的div里面有这个div。所以让父母也运行=服务器并尝试。
< div runat = 服务器 样式 = margin-top：2％;宽度：100％;背景：#FFBF02 ; >
< div id = blocks runat = 服务器 >< / div >
< / div >
希望有所帮助：）
<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.
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
解决方案
debugging your code. And use HtmlGenericControl for HTML Control .
for ex.
HtmlGenericControl div = (HtmlGenericControl)this.FindControl("div1");
I found that you have this div inside another div that is not runat="Server". So make the parent also runat="server" and try.
<div runat="server" style="margin-top:2%; width: 100%; background: #FFBF02;"> <div id="blocks" runat="server"></div> </div>
Hope it helps :)
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