load text into textarea from code behind in asp.net using C#

Question

I've one asp.net page and I want to load text into the textArea control which is in aspx page from into a variable in code behind (C#):

Code behind:

System.Web.UI.HtmlControls.HtmlTextArea Output1 = 
    (System.Web.UI.HtmlControls.HtmlTextArea)(FindControl("textarea1"));       
Output1.Value = Output.ToString();

ASP:

<div style ="width: 78%; float: right; height: 85px; display: block;" 
    class="message_text_box_left">

    <textarea id="textarea1" name="textarea1" cols="30" rows="3" 
        class="message_text_box" title="Share your Idias here..." 
        tabindex="1" onkeyup="addrow_fun();"></textarea>                        
</div>

but it is giving error like

Object reference not set to an instance of an object.

check if 'Output1' did have a value or is null which probably meant it wasn't able to find the control or the control doesn't exists. — Bahamut
– Bahamut, Commented Feb 29, 2012 at 8:01
Are you Finding the control at the right place if its within a panel or something you will need to Find it within that control (parent) — V4Vendetta
– V4Vendetta, Commented Feb 29, 2012 at 8:05

Uwe Keim · Accepted Answer · 2012-02-29 08:18:55Z

3

You should add the

runat="server"

attribute to the text area.

Or, preferable you should use the TextBox ASP.NET control and set the TextMode property to TextBoxMode.MultiLine. Example follows:

Code behind:

Output1.Text = Output.ToString();

ASP:

<div style ="width: 78%; float: right; height: 85px; display: block;" 
    class="message_text_box_left">

    <asp:TextBox ID="Output1" Rows="3" 
        CssClass="message_text_box" ToolTip="Share your ideas here..." 
        TextMode="MultiLine" />                        
</div>

edited Feb 29, 2012 at 8:18

answered Feb 29, 2012 at 7:59

Uwe Keim

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5 Comments

user1230825 Over a year ago

thank you for your respond. that i have alredy done, still getting error.

Uwe Keim Over a year ago

The FindControl method of the page you are calling is not recursive. I.e. if your control is contained within other controls that have the runat="server" attribute set, FindControl returns null.

user1230825 Over a year ago

Yes But, it is return the error Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlInputText' to type 'System.Web.UI.HtmlControls.HtmlTextArea'.

Uwe Keim Over a year ago

@user1230825 I've added an example.

user1230825 Over a year ago

No My Friend, I can not use asp control, I have to use only html textarea here.

Mark Ursino · Accepted Answer · 2012-03-01 21:23:48Z

1

Add runat="server" in *.aspx file. Use Innertext property to set the text value. E.g.

htmlTexarea.InnerHtml = "sample"

edited Mar 1, 2012 at 21:23

Mark Ursino

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answered Mar 1, 2012 at 12:17

user1055073

111 bronze badge

Comments

Rafał Warzycha · Accepted Answer · 2012-02-29 08:08:57Z

0

Add runat="server" to your control
Check your .designer.cs or codebehind .cs file for textarea/textbox declaration and fix it.
Do not use FindControl function (it is not recursive), get control by ID. textarea1.Value = xxx;

edited Feb 29, 2012 at 8:08

answered Feb 29, 2012 at 8:02

Rafał Warzycha

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Comments

user1028089 · Accepted Answer · 2012-02-29 08:10:11Z

0

Try casting to HTML generic control and set it's value or change it to use an asp textbox textmode= multiline

answered Feb 29, 2012 at 8:10

user1028089

Comments

Asken · Accepted Answer · 2012-02-29 08:11:52Z

0

If you add the runat="server" attribute you should be able to use the textarea1.innerText directly.

answered Feb 29, 2012 at 8:11

Asken

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Comments

Juan Andres Zafra · Accepted Answer · 2017-07-13 16:15:34Z

0

Add runat="server" and get value with InnerText from code behind

answered Jul 13, 2017 at 16:15

Juan Andres Zafra

1

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