title: Getting error as Invalid column name C#.NET
body: <p>I am new to C#.net.  I am developing a small application where the data in one drop down list gets populated based on the value selected in another drop down list. Upon viewing the output, I am getting the error <code>Invalid column name 'CategoryBasedList'</code>. Can you please point out where I went wrong. I am attaching the code below. Thanks in advance.</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Data.SqlClient;
  using System.Configuration;
  using System.Data;
  
  
  public partial class UserLogin : System.Web.UI.Page
  {
      protected void Page_Load(object sender, EventArgs e)
      {
         if (!IsPostBack)
          {
            populate();
          }
      }
      protected void ddlCategoryBasedList_SelectedIndexChanged(object sender, EventArgs e)
          {
  
          }
  
      protected void ddlListOfBooks_SelectedIndexChanged(object sender, EventArgs e)
          {
  
          string constr = ConfigurationManager.ConnectionStrings["CONN_STR"].ToString();
          SqlConnection con = new SqlConnection(constr);
          con.Open();
          SqlCommand com = new SqlCommand("Select distinct(CategoryBasedList) from Category where CategoryList = '" +  (ddlListOfBooks.SelectedValue).ToString() + "'", con);
          SqlDataAdapter da = new SqlDataAdapter(com);
          DataSet ds = new DataSet();
          da.Fill(ds);
          ddlCategoryBasedList.DataTextField = ds.Tables[0].Columns["CategoryBasedList"].ToString();
          ddlCategoryBasedList.DataSource = ds.Tables[0];
          ddlCategoryBasedList.DataBind();
  
          }
      protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
          {
  
          }
      public void populate()
      {
      string constr = ConfigurationManager.ConnectionStrings["CONN_STR"].ToString();
      SqlConnection con = new SqlConnection(constr);
      con.Open();
      SqlCommand com = new SqlCommand(" Select distinct(CategoryList) from Category", con);
      SqlDataAdapter da = new SqlDataAdapter(com);
      DataSet ds = new DataSet();
      da.Fill(ds);
      ddlListOfBooks.DataTextField = ds.Tables[0].Columns["CategoryList"].ToString();
      ddlListOfBooks.DataSource = ds.Tables[0];
      ddlListOfBooks.DataBind();
      }
  }
  </code></pre>
  
  <p>The database structure of the above mentioned table - CATEGORY is as follows.</p>
  
  <pre><code>CREATE TABLE [dbo].[Category](
      [[CategoryBasedList]]] [varchar](100) NOT NULL,
      [CategoryList] [varchar](100) NOT NULL,
      [Authors] [varchar](100) NULL
  ) ON [PRIMARY]
  
  GO
  
  SET ANSI_PADDING OFF 
  GO
  </code></pre>