How can I use/reference the selected value (TextBox) from a JavaScript Function into C# Code behind?

Question

1.00/5 (1 vote)

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This is how it works: when the user clicks the TextBox, a palette of colors comes up, and then the user selects the color on a client-side with the JavaScript Function. So, what I need is that value of that color selected. Either get the JS as a text into the (asp:TextBox) to reference the value in C# or get the TextBox value selected directly into C#, if that makes sense.

This is my JavaScript Code:

JavaScript

<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>

This is my aspx Code:

ASP.NET

<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>

This is my C# Code:

C#

private void SaveNumberOfColors() 
{
SqlCommand cmd = null;
string conn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

    string queryString = @"INSERT INTO NUMBER_COLORS " +
    "VALUES(" +
    "@SiteID, @AlphaFirst )";

        using (SqlConnection connection =
                   new SqlConnection(conn))
        {
            SqlCommand command =
                new SqlCommand(queryString, connection);
            connection.Open();
            cmd = new SqlCommand(queryString);
            cmd.Connection = connection;
            cmd.Parameters.Add(new SqlParameter("@SiteID", 
            System.Data.SqlDbType.NVarChar, //SqlDbType value
            20, //The width of the parameter
            "Site_ID")); //The name of the column source
            //Fill the parameter with the value retrieved
            //from the text field
            cmd.Parameters["@SiteID"].Value = foo.Site_ID;

            cmd.Parameters.Add(new SqlParameter("@AlphaFirst", 
            System.Data.SqlDbType.NVarChar, //SqlDbType value
            20, //The width of the parameter
            "AlphaFirst")); //The name of the column source
            //Fill the parameter with the value retrieved
            //from the text field
            cmd.Parameters["@AlphaFirst"].Value = ?????;          

            cmd.ExecuteReader();
        }
    }

Posted 22-May-13 10:26am

Castellon

Updated 22-May-13 12:05pm

v4

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Comments

Prasad Khandekar 22-May-13 16:59pm

Once the form gets posted you will have the value on server side. Where is the problem?

Castellon 22-May-13 17:09pm

I want to use the SelectedValue of the JS, to insert it into SQL db using the ExecuteReader() but I'm not sure how to retrieve that value and add it as a parameter in my C# code. thanks for the help!

Prasad Khandekar 22-May-13 17:17pm

Your code behind can directly access the selected value via COLOR_ALPHA_TEXTBOX2.Text property. However it will be available only when the form gets posted.

Regards,

Castellon 22-May-13 17:22pm

I tried that by setting the AutoPostBack="True" But, I get the following: "Object reference not set to an instance of an object"

Castellon 22-May-13 17:18pm

How can I apply it in my code?

Prasad Khandekar 22-May-13 17:21pm

You must be having an associated code behind file for your aspx file. Please see this MSDN article (http://support.microsoft.com/kb/303247)

Regards,

Castellon 22-May-13 17:49pm

Thank you for the info, but I have referenced my controls.

Castellon 23-May-13 10:35am

Thanks a lot Prasad! I took this approach from MSDN and it works fine.

KK Kod 23-May-13 0:36am

Did you used JQuery in your application ..? if so please go ahead and use jquery ajax on text change event of the text box to update the db with hep of a ashx handler.or else you will get the value with out any complication on post back

4 solutions

Solution 2

Assign the selected color value to an asp:hidden field in JS code and use that hdnField.Value in server side.

Posted 22-May-13 11:12am

vibhu12345

Comments

Castellon 22-May-13 17:50pm

How can I apply what you suggested in my code. Thanks for the help!

Solution 1

Assign the selected value to an asp:hidden field.

Posted 22-May-13 11:11am

vibhu12345

Solution 3

Assign the selected value to an asp. I think it will be enough

Posted 22-May-13 13:04pm

Tayyar Zinde

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KK Kod · Accepted Answer · 2013-05-22T18:42:00

private void SaveNumberOfColors() 
{
SqlCommand cmd = null;
string conn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
 
    string queryString = @"INSERT INTO NUMBER_COLORS " +
    "VALUES(" +
    "@SiteID, @AlphaFirst )";
 
        using (SqlConnection connection =
                   new SqlConnection(conn))
        {
            SqlCommand command =
                new SqlCommand(queryString, connection);
            connection.Open();
            cmd = new SqlCommand(queryString);
            cmd.Connection = connection;
            cmd.Parameters.Add(new SqlParameter("@SiteID", 
            System.Data.SqlDbType.NVarChar, //SqlDbType value
            20, //The width of the parameter
            "Site_ID")); //The name of the column source
            //Fill the parameter with the value retrieved
            //from the text field
            cmd.Parameters["@SiteID"].Value = foo.Site_ID;
 
            cmd.Parameters.Add(new SqlParameter("@AlphaFirst", 
            System.Data.SqlDbType.NVarChar, //SqlDbType value
            20, //The width of the parameter
            "AlphaFirst")); //The name of the column source
            //Fill the parameter with the value retrieved
            //from the text field
            cmd.Parameters["@AlphaFirst"].Value = COLOR_ALPHA_TEXTBOX1.Text;         
 
            cmd.ExecuteReader();
        }
    }