Find HTML Control Using FindControl?
Apr 1, 2010
I add a select control to a ASPX page like below:
hgc = new HtmlGenericControl();
hgc.InnerHtml = @"<select runat='server' id='my_selectlist'>
<option value='volvo'>Volvo</option>
<option value='saab'>Saab</option>
<option value='mercedes'>Mercedes</option>
<option value='audi'>Audi</option>
</select>";
Then in a Button click event, I use the code below, try to get the value selected
HtmlSelect s = (HtmlSelect)hgc.FindControl("my_selectlist");
label.Text = s.Value;
I get a error:"Object reference not set to an instance of an object."Does anyone try it before?
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Feb 3, 2011
I got problem finding the Control ID in my ASP.NET page.
When I try to refer that ID, it always give me:
I am trying to refer this:
[Code]....
I pass this id from here:
[Code]....
This is my code behind which is driving me crazy :(
[Code]....
When I use label to display the STRING INTIME, IT GIVES ME "textboxCashier1In"
BUT WHEN I DO THIS:
[Code]....
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Jun 10, 2010
I have a PlaceHolder control inside of a ListView that I am using to render controls from my code behind. The code below adds the controls:
TextBox tb = new TextBox();
tb.Text = quest.Value;
tb.ID = quest.ShortName.Replace(" ", "");
((PlaceHolder)e.Item.FindControl("ph_QuestionInput")).Controls.Add(tb);
I am using the following code to retrieve the values that have been entered into the TextBox:
foreach (ListViewDataItem di in lv_Questions.Items)
{
int QuestionId = Convert.ToInt32(((HiddenField)di.FindControl("hf_QuestionId")).Value);
Question quest = dc.Questions.Single(q => q.QuestionId == QuestionId);
TextBox tb = ((TextBox)di.FindControl(quest.ShortName.Replace(" ","")));
//tb is always null!
}
But it never finds the control. I've looked at the source code for the page and the control i want has the id:
ctl00_cphContentMiddle_lv_Questions_ctrl0_Numberofacres
For some reason when I look at the controls in the ListViewDataItem it has the ClientID:
ctl00_cphContentMiddle_lv_Questions_ctrl0_ctl00
Why would it be changing Numberofacres to ctl00? Is there any way to work around this?
UPDATE:
Just to clarify, I am databinding my ListView in the Page_Init event. I then create the controls in the ItemBound event for my ListView. But based on what @Womp and MSDN are saying the controls won't actually be created until after the Load event (which is after the Page_Init event) and therefore are not in ViewState? Does this sound correct?
If so am I just SOL when it comes to retrieving the values in my dynamic controls from my OnClick event?
UPDATE 2:
So i changed the code i had in my Page_Init event from:
protected void Page_Init(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
//databind lv_Questions
}
}
to:
protected void Page_Init(object sender, EventArgs e)
{
//databind lv_Questions
}
And it fixed my problem. Still a little confused as to why I want to databind regardless of whether it's a postback or not but the issue is resolved.
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Mar 31, 2010
So all I want to do is simply find a user control I load based on a drop down selection. I have the user control added but now I'm trying to find the control so I can access a couple properties off of it and I can't find the control for the life of me. I'm actually doing all of this in the master page and there is no code in the default.aspx page itself.
MasterPage.aspx
[Code]....
MasterPage.cs
protected void goToSelectedPage(object sender, System.EventArgs e)
{
temp1 ct = this.Page.Master.LoadControl("temp1.ascx") as temp1;
ct.ID = "TestMe";
this.UpdatePanel1.ContentTemplateContainer.Controls.Add(ct);
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//This is where I CANNOT SEEM TO FIND THE CONTROL ////////////////////////////////////////
protected void lnkSave_Click(object sender, System.EventArgs e)
{
UpdatePanel teest = this.FindControl("UpdatePanel1") as UpdatePanel;
Control test2 = teest.ContentTemplateContainer.FindControl("ctl09") as Control;
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string maybe = test3.Col1TopTitle;
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Here I don't understand what it's telling me. for "par" I get "ctl09" and I have no idea how I am supposed to find this control. temp1.ascx.cs
protected void Page_Load(object sender, EventArgs e)
{
string ppp = this.ID;
string par = this.Parent.ID;
}
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Apr 20, 2010
Object reference not set to an instance of an object. when I try to access these dynamically created controls using FindControl.
I have a dynamically created control within a table cell. The table itself is contained within a page that has a master page. I've tried so many different ways to access this control.
Below is the latest iteration
AttrTable is the asp table, and row.Attr_Type is the name I've given to the control (it iterates through a datatable to set the names for the control)
tmpVal = CType(AttrTable.FindControl("TD_" & row.Attr_Type).FindControl(row.Attr_Type), DropDownList).Text
Below are various ways I've tried to access the control:
Dim form As Control = Page.Master.FindControl("form1")
Dim content1 = form.FindControl("ContentPlaceHolder1")
[Code]....
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May 18, 2010
I have problem that how to get html control id in c# code behind page.?
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Feb 27, 2010
I have an asp:table control that I construct dynamically. I place a few textboxes in it within a for loop and assign their IDs in code. I'll include an abbreviated code fragment showing how I'm doing this:
[Code]....
The page then displays correctly and the ID is set correctly when I view the source, but when I try to access the textbox later when the form is submitted the call to FindControl(idStr) returns null no matter what I do.
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Mar 7, 2011
I try to run each control and then check what html did it render.
But this seems to me as an inaccurate method as whenever we add or remove the properties, or events of the control,the rendered HTML changes. Is there any book/tutorial/article to explain what is the standard HTML rendered by each asp.net control.
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Sep 22, 2010
how to find html anchor control in telerik:radgrid ?
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Oct 1, 2010
I have a Sidemenu item in my ASP.NET application like below. There are two types of users in my application (Associates, Managers).When ever Associate Login then I have to disable Manager link. I am not able find visible property in codebehind since it is a HTML control. So need your support how to handle this
<ul>
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<li><a href="Manager.aspx id="lnkManager">Manager</a></li>
</ul>
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Nov 15, 2010
I'm sure I'm doing something wrong here, but I cannot figure it out.
This is in my aspx page:
[code]....
And this is in my aspx.vb page:
[code]....
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Dec 13, 2010
I have a situation where I need to dynamically disable certain controls. I will not be knowing the type of control. I tried to use FindControl(""), but this does not have the "Enabled" property, it only has "Visible" property.
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Aug 10, 2010
How do we code "findcontrol" with a third party control? I tried "TextBox" for Namespace="FreeTextBoxControls" Assembly="FreeTextBox" and it threw an error:
Object reference not set to an instance of an object.
Here is the offending line:
Dim Body As String = Convert.ToString(CType(lsvBlocks.InsertItem.FindControl("FreeTextBox"), TextBox).Text)
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Feb 17, 2011
I have a literal8 inside panel1 and panel1 inside datalist1 ..
i wanna insert the value in literal1 on page load event using query string ...
ERROR on Page Load : Object reference is not set to the instance of an object
how to make this code workin ?
Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreInit
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Mar 1, 2011
How can I access to the CancelPushButton ?
This doesn't work ! it returns always null !!
var cancelButton = ChangeUserPassword.FindControl("CancelPushButton");
[Code]....
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Mar 11, 2011
I use the following method to find a control on an asp.net page recursively:
/// <summary>
/// Searches recursively for a server control with the specified id parameter.
/// </summary>[code]...
I hit a problem because it was returning the wrong control. I tracked the problem down to the standard FindControl method, and fixed it by checking that the id of the control returned did actually match the one requested like this:
foundControl = start.FindControl(id);
if (foundControl != null && foundControl.ID == id)
return foundControl;
My question is why does start.FindControl(id) ever return a control that does not match the id requested?
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Feb 9, 2011
Consider the following code, adding 2 textboxes with the same ID (oops):
protected void Page_Load(object sender, EventArgs e)
{
string TextBoxName = "TextBox1";
Panel p = new Panel();
TextBox t = new TextBox();
t.ID = TextBoxName;
p.Controls.Add(t);
if (p.FindControl(TextBoxName) == null) // <-------*******
{
TextBox t2 = new TextBox();
t2.ID = TextBoxName;
p.Controls.Add(t2);
}
Page.Form.Controls.Add(p);
}
The code is designed to stop adding the same ID twice. However, the Panel.FindControl() method is not finding a control that was added in the previous line of code.
Am I using this in the wrong way?
I mean - sure - I could manually iterate through the controls in the next level, like:
string TextBoxName = "TextBox1";
Panel p = new Panel();
TextBox t = new TextBox();
t.ID = TextBoxName;
p.Controls.Add(t);
TextBox t2 = new TextBox();
t2.ID = TextBoxName;
bool duplicateFound = false;
foreach( Control c in p.Controls )
{
if(c.ID == TextBoxName)
{
duplicateFound = true;
break;
}
}
if( duplicateFound )
{
t2.ID = TextBoxName + "__0";
p.Controls.Add(t2);
}
But I don't understand why this isn't working, whereas Placeholder controls and UserControls work fine.
The reason I am using Panels is for CSS styling. body > div > input - but still - it isn't working.
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Mar 18, 2011
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I know that the issue is not my stored procedure becasue if I use static values for the parameters in the code behind, the values are updated by the stored procedure.
I placed two plain textboxes and a button on the ASPX form and create a button click event for that button using the same code I use for the butten click event in the formview. When I add values to the non-databound textboxes, the data is updated correctly.
The question is, why can I not get the updated/changed values from textboxes in the FormView control?
Here is my ASPX code:
[Code]....
[Code]....
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Mar 8, 2011
I want to change the text of the user name text box which is inside a log in view on selected index chaged event of a drop down list.
this is my code:
[Code]....
but both ddl and tb are null
Anyone knows how can I find the controls in code behind?
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Jan 6, 2010
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Process flow:
controls:d1 and d2
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d2 is using codebehind code to load the item based on the selected value in the d1 : Not working
How to findthe control in the edit template to display item value for d2.
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How to use Control Parameter with SQLDataSource When FindControl is required?
[Code]....
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I am realizing a table with multiple rows for a Sharepoint webpart.
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Essentially this html control would be a row used for my html table.
At the moment i am doing a row like this in the main class :
[Code]....
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[Code]....
there are no differences i can see in the pages that do show up and the one that cant be found (links.aspx).
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I need about 6 or 7 of these links on the master to pages in the home folder.
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