FindControl CodeBehind Issue - c#

I have the following code in my aspx file:
<input type="text" runat="server" id="test" name="test" onBlur="OnBlurFunction()"/>
When I click a submit button:
<asp:Button runat="server" id="SubmitButton" OnClick="SubmitButton" Text="Submit" />
The function "SubmitButton" contains the following:
System.Diagnostics.Debug.WriteLine(this.FindControl("test"));
When I run this, it always prints out a blank value and I'm not sure why. If I set the value in the HTML line as follows:
<input type="text" runat="server" id="test" name="test" value="hello" onBlur="OnBlurFunction()"/>
It prints "hello" with no issues. But when I manually change the value in the text box to something else, it always to print the first value out. It's as if something isn't dynamic. Am I doing something fundamentally wrong here?

Try This -
HtmlInputText tb1 = this.test;
System.Diagnostics.Debug.WriteLine(tb1.Value);
This is the thread - find control and html tags

You must use parent control(like asp:panel or runat server div) instead of this to call FindControl method.
Like this:
pnl1.FindControl("test")

Related

Get the value of a textbox in codebehind (declared using HTML in an asp.net page)

I want to get the value of my input tag into my C#.
<div id="datetimepicker2" class="input-append">
<input data-format="MM/dd/yyyy HH:mm:ss PP" type="text"></input>
<span class="add-on">
<i data-time-icon="icon-time" data-date-icon="icon-calendar">
</i>
</span>
</div>// what should we use here?
The value is set by the user of the page.
I did't understand which control value you want to get. But If you want to get input element value into the code behind, you need to set runat="server" attribute, because this is a simple html element not a Asp control.
Add runat="server" and id="your_id" and you should have access to them.
for example:
<input type="text" value="Username" class="input-text autoclear"
runat="server" id="myTextBox" />
than you can simply get value of input box like this:
string myStringFromTheInput = myTextBox.Value;
For more options please See here
Try this
Add name for your input type
<input data-format="MM/dd/yyyy HH:mm:ss PP" name="txtBox1" type="text"></input>
and try this way for get value in codebehind
string value=Request.Form["txtBox1"];
You can access all your submitted form data at server side by looking into the form Request object.
Ex. Request.Form["txtDate"] OR Request["txtDate"].
Naming the html elements makes easier to look into form collection for specified element.
If what you posted is your actual code, you have an extra space in your closing tag
</asp: TextBox>
Should be
</asp:TextBox>
and then txt_todata.text should work

Clear <input> field from code behind

To pass values from javascript to the code behind after a postback I use this code:
string strRowNumberTblOne = Request.Form["iRowNumberTblOne"];
<input type="hidden" id="iRowNumberTblOne" name="iRowNumberTblOne" value="" />
Is there a way to clear the input field from the code behind?
The Request.Form is read only.
Add runat="server". Then set its Value property.
Try this Instead of you can use Hidden TextBox , like this
<asp:TextBox ID="TextBox2" style="display:none" runat="server"></asp:TextBox>
In JavaScript
varResult = document.getElementById('<%= TextBox2.ClientID%>');

How to reference code behind variable in ASPX?

I'm not sure why when referencing a code behind variable in an asp.net control, I get the text of the reference:
<%=this.Person.Contact.Emails[0].EmailAddress%>
This outputs the literal reference text:
<asp:TextBox ID="EmailAddress" runat="server" Text="<%=this.Person.Contact.Emails[0].EmailAddress%>"></asp:TextBox>
This renders the variable value:
<input id="testfield" type="text" value="<%=this.Person.Contact.Emails[0].EmailAddress%>" />
Any ideas how I can get the variable value in the asp.net control?
You could say:
EmailAddress.Text = this.Person.Contact.Emails[0].EmailAddress
in your code behind
I prefer the solution in Code Behind in hunter's solution but another option would be to use data binding with #:
<asp:TextBox ID="EmailAddress" runat="server" Text="<%# this.Person.Contact.Emails[0].EmailAddress%>" />
But then you have to bind the server control in code-behind:
EmailAdress.DataBind();
The = sign is like a call to Response.Write() at this place and just outputs whatever follows as text.

Unable to get value Textbox by id in javascript

I have text boxes and it has values let say. I am calling my javascript method on one of textbox 'onblur'. my function is:
function CalculateExpectedProductPrice() {
alert("hi i called");
var originalPrice = document.getElementById('hdnSelectedProductPrice').value;
var numberOfLicenses = document.getElementById('txtNumberOfLicense').value;
var enteredAmount = document.getElementById('txtAmount').value;
alert(originalPrice);
alert(numberOfLicenses);
alert(enteredAmount);
}
i am getting alert message as ""hi i called". but not further.
But some i am not getting values of these controls.
*Edited:* My HTML is :
<asp:HiddenField ID="hdnSelectedProductPrice" runat="server" />
<asp:TextBox ID="txtAmount" runat="server" Width="250px"></asp:TextBox>
<asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:TextBox ID="txtNumberOfLicense" runat="server" Width="35px" ></asp:TextBox>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="txtNumberOfLicense" EventName="" />
</Triggers>
</asp:UpdatePanel>
Will there any impact master-content page . because script is in content page and html also on same content page.Also let me know you, I am using wizard control where as all these controls are resides on second step of wizard. will that make any impact ?
Edited:
I think wizard control making here matter. As i started my firebug and review the generated html it assign the Id dynamically to those controls which are inside the wizard. thats why javascript unable to find the expected control .
eg for txtAmount text box which is inside the wizard control getting name as :
ctl00_ContentPlaceHolder1_Wizard1_txtAmount
but certainly i would not prefer to use this generated Id. So is there any remedy to find control inside the wizard control and get - set values ?
get id of the control as shown below
var enteredAmount = document.getElementById('<%=txtAmount.ClientId%>').value;
It's impossible to say for certain with your not having quoted your HTML (!), but the usual reason for this is confusion between the id and name attributes. document.getElementById works with the id attribute, but people tend to think it works with the name on input fields, which it doesn't (except for on IE, where getElementById is broken).
(The other thing to remember is that id values must be unique on the entire page, but looking at the IDs you quoted, I suspect you're okay on that front.)
Update: It works if you use ids:
HTML:
<form>
<input type='hidden' id='hdnSelectedProductPrice' value='10'>
<input type='text' id='txtNumberOfLicense' value='2'>
<input type='text' id='txtAmount' value='3'>
<br><input type='button' id='theButton' value='Click Me'>
</form>
Live copy
As T.J. mentioned we really need to see your html code, without seeing it it could be that you are looking for an elements attributes.
So lookup the element as you are already with
var element = document.getElementById('product');
Once you have the element you can query its attributes
var price = element.getAttribute('price');
If its "ASP.net server control" then you will have to do it like this:
var originalPrice = document.getElementById('<%=hdnSelectedProductPrice.ClientID %>').value;
if you use Asp.Net 4.0 and your textbox is unique on the entirepage you can add ClientIDMode="Static" in attribute of your textbox
<asp:TextBox ID="txtAmount" runat="server" Width="250px" ClientIDMode="Static"></asp:TextBox>

ASP.Net: ClientID not correct in code-behind of a user control

The following code does not work. The markup is in a User Control and I suppose that's why ClientID returns the wrong prefix for the TextBox id.
Markup:
<INPUT id="txtName" runat="server" maxlength="50" style="WIDTH:100px">
<INPUT type="button" value="Find Your Doctor" id="btnFind" runat="server"
style="MARGIN-LEFT:10px;WIDTH:130px">
Code-Behind:
btnFind.Attributes.Add("onClick",string.Format("DoctorLink
('{0}',document.getElementById('{1}').value,{2});",
row["ZipCode"],
txtName.ClientID));
Results in browser:
<input name="DoctorsMainArea1$ctl01$txtName" type="text"
id="DoctorsMainArea1_ctl01_txtName" maxlength="50" style="WIDTH:100px" />
<input name="DoctorsMainArea1$ctl01$btnFind" type="button"
id="DoctorsMainArea1_ctl01_btnFind" value="Find Your Doctor" style="MARGIN-
LEFT:10px;WIDTH:130px" onClick="PrepareDoctorLink('90210',
document.getElementById('DoctorsMainArea1_ctl00_txtName').value);" />
As you can see, the parameter for the JavaScript call is DoctorsMainArea1_ctl00_txtName, but the actual id of the input element is DoctorsMainArea1_ctl01_txtName.
Any idea how to fix this? jQuery? I am not so much interested in an explanation of what's going on (maybe there is another control on this page that is interfering), but a more robust way to solve the problem.
I don't know which asp.net version you are using but in 4.0 you can declare inside any server control ClientIDMode="static" and it will give you the exact id in browser.
Example:
<asp:Textbox id="txtName" runat="server" ClientIdMode="static"/>
Others are predictable, inherit and it can be used with ClientIdRowsuffix.Can be used at page level and even on master pages and even in web.config file.
Example on web.config file:
<system.web>
<Pages clientIDMode="predictable"/>
other system web properties
</system.web>
Watched Craig shoemaker's Video at tekpub, you can also read more about it at Rick's bloglink text. It's pretty cool tho.
You should try moving the code that adds the onclick attribute to the button in the PreRender event (or OnPreRender override) in your page or user-control. That should probably get the ClientID right.
A fast solution:
btnFind.Attributes.Add("onClick",string.Format("DoctorLink
('{0}',document.getElementById('{1}').value,{2});",
row["ZipCode"],
"DoctorsMainArea1_ctl01_" + txtName.ClientID));
This happens because you have a content placeholder in your page somewhere.
another solution:
html tag:
<input type="text" name="txtName" id="txtName" />
code-bind:
string txtName_value = Request.Forms["txtName"];
and you can get the value
just use the html control.

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