How to reference code behind variable in ASPX? - c#

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.

Related

FindControl CodeBehind Issue

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")

ASP.net shorthand in TextBox

I am trying to do the following:
<asp:TextBox ID="txtName" runat="server" Text="<%= Name %>" />
When I execute my page it gets output as <%= Name %> instead of actually doing a response.write.
I tried modifying it to use the <% Response.Write(Name) %> instead but it did the same thing, putting the text there instead.
I can do this just fine:
<input type="text" value="<%= Name %>" />
That will actually work. Why doesn't this work when I use the TextBox control? Is there another way I'm supposed to do this?
Either use code behind:
txtName.Text = Name;
Or, add Page.DataBind() in your code behind and change the syntax of your control to:
<asp:TextBox ID="txtName" runat="server" Text="<%# Name %>" />
Note the # rather than the =. # represents a data-binding expression
Because the control is rendered differently than a literal. Use the codebehind to set the Text property.

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.

Why can't I set the asp:Label Text property by calling a method in the aspx file?

Can somebody please explain this to me:
I have a label and I want to be able to set the Text property by calling a method in the aspx file. It works fine if I set the property in code behind, but I really want to set this property in the aspx file.
I have tried a couple of things, but what I expected to work was this:
<asp:Label ID="Label1" runat="server" Text=<%# GetMyText("LabelText") %> />
I get no errors when doing this, but my method is never called and the Text property is left empty.
Is it not possible to set property values to server side controls directly in the aspx without using resources or use hard coded values?
Update: My first try was:
<asp:Label ID="Label1" runat="server" Text=<%= GetMyText("LabelText") %> />
But that results in the following error:
Server tags cannot contain <% ... %> constructs.
The syntax =<%# ... %> is Data binding syntax used to bind values to control properties when the DataBind method is called.
You need to call DataBind - either Page.DataBind to bind all the controls on your page, or Label1.DataBind() to bind just the label. E.g. add the following to your Page_Load event handler:
if (!IsPostBack)
{
this.DataBind();
// ... or Label1.DataBind() if you only want to databind the label
}
Using Text='<%= GetMyText("LabelText") %>' as others have proposed won't work as you'll find out. This syntax is inherited from classic ASP. It can be used in some circumstances in ASP.NET for inserting dynamic values in static HTML, but can not be used for setting propeties of server controls.
The sysntax you are looking for is <%= %> the # is for data binding. So your code should read:
<asp:Label ID="Label1" runat="server" Text='<%= GetMyText("LabelText") %>' />
EDIT: This answere is incrrect
I am leaving this answer here because lots of people agreed with me that this is infact the correct answer, but it will not work. This line of code will produce the following HTML output:
<span id="Label1"><%= GetMyText("LabelText") %></span>
Try this:
<asp:Label ID="Label1" runat="server" Text='<%= GetMyText("LabelText") %>' />
Edit
Yep. I was wrong. #Joe was right.
However, THIS works (and I'm not sure what the difference is):
<asp:Label ID="Label1" runat="server"><%= GetMyText("LabelText") %></asp:Label>
CodeBehind:
protected string GetMyText(string input)
{
return "Hello " + HttpUtility.HtmlEncode(input);
}

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