How to Bind dropdown list from code behind with data from database.

vijay rags

Dear All,

                 I want to populate a dropdownlist from database in code behind. I tried with the following code but while binding it is throwing an error "Object Reference not set to an Instance". Please find the code appended.Thanks in advance.

Code:

Sample.aspx:



Sample.aspx.cs

System.Data.SqlClient.SqlConnection conn = null;
                SqlDataReader drFailureCode = null;
                string sqlQuery = string.Empty;

System.Data.SqlClient.SqlConnection conn = null;
                SqlDataReader drFailureCode = null;
                string sqlQuery = string.Empty;
                sqlQuery = "select distinct * from ";
                conn = SqlHelperConnection.getConnection();
                drFailureCode = SqlHelper.ExecuteReader(conn, CommandType.Text, sqlQuery);

                if (drFailureCode.HasRows)
                {
                    ddlSample.DataSource = drFailureCode;
                    ddlSample.DataTextField = "FailureID";
                    ddlSample.DataValueField = "FailureName";
                    ddlSample.DataBind();
                }
                drFailureCode.Close();
                ddlSample.Items.Insert(0, new ListItem("--Select--", "0"));

Thanks In Advance.

7 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sukesh Marla14y ago
I copied your code and created a sample code, Just Replaced Sql Helper with common SqlCommand and its working fine...
U just try by that way and by that you may get reason for the actual error.

Hope It Helped. Please Check This is Currect Answer.
Naresh Avari14y ago
Hi Vijay, Can you use the following sample:
string query = string.Empty;
query = "SELECT * FROM Categories";
using (SqlConnection con = new SqlConnection(connStr))
{
con.Open();
using (SqlCommand cmd = new SqlCommand("SELECT * FROM Categories", con))
{
using (SqlDataReader dr = cmd.ExecuteReader())
{
while (dr.Read())
{
ListItem li = new ListItem();
li.Value = dr["CategoryId"].ToString();
li.Text = dr["CategoryImage"].ToString();
ddlCategory.Items.Add(li);
}
}
}
}
Sukesh Marla14y ago
There was someting written inside sqlhelper or may be some issue with something else, I can help u but i have to take a look at you code, So share that as zip if you can.
vijay rags14y ago
Hi, I already shared the code.Beyond this I can't. Hope you understand. Any alternate solution will be helpful.
Sukesh Marla14y ago
Can u share code...i check and revert back...
vijay rags14y ago
Hi, Thanks for your reply. I am getting the list of values but while binding only it is throwing error (i.e., ddlSample.DataSource line.)Whether we need to set any properties for DropDownList.
Sukesh Marla14y ago
It was some issue with SQLHelper calsses.

Hope It Helped. Please Check This is Currect Answer.