What is the best way to access the value chosen in a TextBox using a JavaScript Function in C# code-behind?

aspx.cs:

<script type="text/javascript">
    $(function () {
        //ALPHA
        $('#COLOR_ALPHA_TEXTBOX1').colorPicker({ pickerDefault: "E1E1E1", colors: ["E1E1E1", "33CC00", "FFF000", "CC0000", "996600", "FF9900", "303030", "0066FF", "F9A7B0", "9A0EEA"], transparency: true });
        $('#COLOR_ALPHA_TEXTBOX2').colorPicker({ pickerDefault: "E1E1E1", colors: ["E1E1E1", "33CC00", "FFF000", "CC0000", "996600", "FF9900", "303030", "0066FF", "F9A7B0", "9A0EEA"], transparency: true });
    });
</script>

<asp:Table ID="Table" runat="server" style="border: medium solid #000000">
<asp:TableRow>
    <asp:TableCell ID="TC2BC" HorizontalAlign="left" VerticalAlign="top">
            <asp:TextBox ID="COLOR_ALPHA_TEXTBOX1" type="text" runat="server" Visible="False"></asp:TextBox>
    </asp:TableCell>
</asp:TableRow>
<asp:TableRow>
    <asp:TableCell ID="TC9BC" HorizontalAlign="left" VerticalAlign="top" >
    <asp:TextBox ID="COLOR_ALPHA_TEXTBOX2" type="text" runat="server" Visible="False"></asp:TextBox>
    </asp:TableCell>
</asp:TableRow>
</asp:Table>

I attempted to utilize the following code in the cs file:

COLOR_ALPHA_TEXTBOX1.SelectedValue 

However, I could not find that option in C#; Can anyone suggest an alternative solution? Thank you for your assistance!

Answer №1

To start, make sure to correct the ASPX markup by changing the first tag to in order for the tags to match properly.

Next, remember that the TextBox control does not have a SelectedValue property, but rather a Text property.

Lastly, keep in mind that you cannot directly access inner nested controls; you must use FindControl method to locate them:

(TextBox)Table.Rows[0].Cells[0].FindControl("COLOR_ALPHA_TEXTBOX1").Text

Answer №2

What is the reason behind attempting to retrieve the selected value from a textbox? It's recommended to utilize

  COLOR_ALPHA_TEXTBOX1.Text 

within the codebehind.

Additionally, avoid using

Visible="false"

since it will prevent the control from being rendered. If you need to conceal a control (although it's unclear why in this scenario), use:

 style="display:none"

Are there any other libraries being used with this control? It's not clear how you are implementing a "color" picker without more code. Are jQuery or the AjaxControlToolkit involved?

Answer №3

There are two common causes for this issue:

  • The .cs file may not be inheriting from System.UI.Page
  • The .aspx file might not have the correct value set in the codebehind attribute:

<%@ Page Language="c#" AutoEventWireup="true" Codebehind="SamplePage.aspx.cs" Inherits="Namespace.SamplePage"%>

However, when dealing with a textbox, using the property SelectedValue is incorrect. Instead, you should use Text:

COLOR_ALPHA_TEXTBOX.Text 

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