Question

I have a java script variable and I want to use it into my sqldatasourse how can I do this. Here is my java script code

var div = document.getElementById('main_content').offsetHeight;
            var length = Mah.round(div / 400);

And I want to use variable length here in select command

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:qbuyConnectionString1 %>" 
         SelectCommand="SELECT TOP variable * FROM [advertisement] WHERE ([enable] = @enable) ORDER BY NEWID()">
        <SelectParameters><asp:Parameter DefaultValue="1" Name="enable" Type="Int32" /></SelectParameters>
</asp:SqlDataSource>

Answer 1

The easiest solution based on how you are trying to do this is a combination of some of the aforementioned suggestions.

1. Create a server-side ASP.NET hidden field control in your page.
2. Set the server-side hidden field control to the JavaScript variable value.
3. In the _Selecting event which fires prior to the database being accessed, set the ‘Parameter’ value to that of the hidden server-side control.

Step 1:

<!--Create an ASP.NET hidden field server control-->
<asp:HiddenField ID="HiddenField1" runat="server" />

Step 2:

//JavaScript you were using populating the 'length' variable:
var div = document.getElementById('main_content').offsetHeight;
var length = Mah.round(div / 400);
//Now set the hidden field's value to your JS variable value:
document.getElementById('<%= HiddenField1.ClientId %>');

Step 3:

protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
{
    //The 'Selecting' event fires *prior* to the wired up Select method being called.
    //This is the spot to add in or modify any of the parameter values:
    e.Command.Parameters["LengthParameter"].Value = this.HiddenField1.Value;
}