Same select query in same button event

[ammu 24]

I am trying to insert details in the database using ASP.NET code. If any one of the data or field value is already existing,it will show an alert message 'already existing'.

I will show the code:

 protected void btnSave_Click(object sender, EventArgs e)
        { 
 
            lblMessage.Text = string.Empty;
            if (txtFName.Text == String.Empty || txtLName.Text == String.Empty || txtAccount.Text == String.Empty || txtAddress.Text == String.Empty || txtJoiningDate.Text == String.Empty || txtMailID.Text == String.Empty || txtPassword.Text == String.Empty)
            {
                lblMessage.Text = "Please Enter Valid Values";
            }
 
 
            else
            {
 
                try
                {
                    int lastInserted=0;
                    DataSet ds = new DataSet();
                    SqlConnection conn = new SqlConnection(connstring);
                        conn.Open();
                        SqlCommand Cmd = new SqlCommand("EmployeeDatabase.dbo.insertEmployeeDetails", conn);
                        Cmd.CommandType = CommandType.StoredProcedure;
                        Cmd.Parameters.Add("emp_id", SqlDbType.BigInt);
                        //Cmd.Parameters["emp_id"].Value = txtid.Text;
                        Cmd.Parameters["emp_id"].Value = txtid.Text;
                        Cmd.Parameters.Add("empfirstname", SqlDbType.VarChar);
                        Cmd.Parameters["empfirstname"].Value = txtFName.Text;
                        Cmd.Parameters.Add("emplastname", SqlDbType.VarChar);
                        Cmd.Parameters["emplastname"].Value = txtLName.Text;
                        Cmd.Parameters.Add("accnumber", SqlDbType.VarChar);
                        Cmd.Parameters["accnumber"].Value = Convert.ToInt32(txtAccount.Text);
                        Cmd.Parameters.Add("joiningdate", SqlDbType.DateTime);
                        Cmd.Parameters["joiningdate"].Value = txtJoiningDate.Text;
                        Cmd.Parameters.Add("address", SqlDbType.VarChar);
                        Cmd.Parameters["address"].Value = txtAddress.Text;
                        Cmd.Parameters.Add("typeofuser", SqlDbType.VarChar);
                        Cmd.Parameters["typeofuser"].Value = ddlUser.SelectedItem.ToString();
                        Cmd.Parameters.Add("emailid", SqlDbType.VarChar);
                        Cmd.Parameters["emailid"].Value = txtMailID.Text;
                        Cmd.Parameters.Add("active", SqlDbType.Bit);
                        Cmd.Parameters["active"].Value = Convert.ToInt32(ddlActive.SelectedValue);
                        Cmd.Parameters.Add("password", SqlDbType.VarChar);
                        Cmd.Parameters["password"].Value = txtPassword.Text;
 
                        //int rows = Cmd.ExecuteNonQuery();
                        SqlDataReader reader = Cmd.ExecuteReader();
                        while (reader.Read())
                        {
 
 
 
                           Cmd = new SqlCommand("select * from EmployeeDatabase.dbo.Employee_Table where Emp_ID="+lastInserted, conn);
 
                            //conn.Open();
                            //Cmd.ExecuteNonQuery();
                            //lastInserted = Int32.Parse(Cmd.ExecuteScalar().ToString());
                            lblMessage.Text = "Succesfully added";
                        }
                        reader.Dispose();
                        Cmd.Dispose();
                        conn.Close();
                        grdEmployee.DataSource = ds;
                        grdEmployee.DataBind();
 
                        conn.Open();
                        //Cmd = new SqlCommand("select * from EmployeeDatabase.dbo.Employee_Table where Emp_ID="+lastInserted, conn);
                      Cmd = new SqlCommand("SELECT Email_ID FROM EmployeeDatabase.dbo.Employee_Table WHERE  Email_ID='" + txtMailID.Text + "'", conn);
 
                         reader = Cmd.ExecuteReader();
 
                        if (reader != null && reader.HasRows)
                        {
                            lblMessage.Text = "Emailid already exist";
                        }
                        else
                        {
                            lblMessage.Text = "successfully added";
                        }
 
                        reader.Dispose();
                        SqlDataAdapter da = new SqlDataAdapter(Cmd);
                        da.Fill(ds,"Employee_Table");
                        da.Dispose();
                        Cmd.Dispose();
                        grdEmployee.DataSource = ds.Tables["Employee_Table"];
                        grdEmployee.DataBind();
                        conn.Close();
}

But it is showing an error the ilistsource does not contain any data sources.

What does it mean?

[Rabbit]

I don't know what insertEmployeeDetails does but it sounds like it inserts a new record. You're probably hitting up against a unique index conflict.