title: Exception Details: System.Data.SqlClient.SqlException: Invalid column name 'PRC0000001'
body: <p>i keep getting this error, i dont know why, im still new to c#. kindly help me figure this out please. i have two dropdownlist that would populate data based on first dropdownlist selected value.</p>
  
  <p>when i select a value on the first dropdownlist, i get that error..</p>
  
  <p>here is my code..</p>
  
  <pre><code>protected void Page_Load(object sender, EventArgs e)
      {
          if (!IsPostBack)
          {
              //read sql server connection string from web.config file
              string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
              SqlConnection conn = new SqlConnection(constring);
              DataTable dt = new DataTable("emed_province");
  
              using (conn)
              {
                  conn.Open();
                  SqlCommand comm = new SqlCommand("SELECT *  FROM emed_province ORDER BY PROVINCE_NAME ASC", conn);
                  SqlDataAdapter adptr = new SqlDataAdapter(comm);
                  adptr.Fill(dt);
              }
  
              ddlProvince.DataSource = dt;
              ddlProvince.DataTextField = "PROVINCE_NAME";
              ddlProvince.DataValueField = "PROVINCE_CODE";
              ddlProvince.DataBind();
          }
      }
  
      protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e)
      {
          string constring = ConfigurationManager.ConnectionStrings["AccreString"].ConnectionString;
          SqlConnection conn = new SqlConnection(constring);
          DataTable dt = new DataTable("emed_province");
  
          using (conn)
          {
              conn.Open();
              SqlCommand comm = new SqlCommand("SELECT CITY_NAME FROM emed_city WHERE PROVINCE_CODE ="+ddlProvince.SelectedValue, conn);
              SqlDataAdapter adptr = new SqlDataAdapter(comm);
              adptr.Fill(dt);
          }
  
          ddlCity.DataSource = dt;
          ddlCity.DataTextField = "CITY_NAME";
          ddlCity.DataValueField = "CITY_CODE";
          ddlProvince.DataBind();
      }
  }
  </code></pre>