[RESOLVED] Updating dropdown list in the datalist

Hi there,

I have a datalist where by have a dropdown list that populate from database. But when I update the information, the system giving me this error:

System.NullReferenceException: Object reference not set to an instance of an object.

And focus in this line 

String Category =  ((DropDownList)e.Item.FindControl("Category")).Text;

Below is my code:

                            RepeatColumns="1" DataKeyField="ID" 
                            class="Full-table" CellPadding="4" ForeColor="#333333"
                            OnItemDataBound="dlPromotionList_ItemDataBound"
                            OnEditCommand="dlPromotionList_EditCommand"
                            OnCancelCommand="dlPromotionList_CancelCommand"
                            OnDeleteCommand="dlPromotionList_DeleteCommand"
                            OnUpdateCommand="dlPromotionList_UpdateCommand"
                            >
                            
                            
                                


















                                    

                                    
                                    
                                
                                    
 
  
                                        
                                       
                                    
                                
                                
                                    
 
                                    
 
                                        
                                        
                                    
                                
                                
Category
                                    
 
                                    
 
                                          
                                    
                                
                                                                
                                    
 
                                    
 
                                           
                                       
                                        
                                    
                                
                            
                            
                            
                            
                            
                            


















                                                                

                                    
                                    
                                    
                                    
                                    
                                    
 
  
                                    
                                
                                
                                    
 
                                    
 
                                    
                                
                                
Category
                                    
 
                                    
  
                                        
                                        
                                    
                                
                                
                                    
 
                                    
    
                                           
                                    
                                
                            
                            

                            

                        

Code behind: onItemBound

protected void dlPromotionList_ItemDataBound(object sender, DataListItemEventArgs e)
        {
            if (e.Item.ItemType == ListItemType.EditItem)
            {
                DropDownList Category = (DropDownList)e.Item.FindControl("PromotionCategory");
                String catID = ((Label)e.Item.FindControl("lblCat")).Text;

                bindCat(Category, catID);
               
            }
        }

        protected void bindCat(DropDownList Category, string catID) {
            string sqlQuery;
            //  sqlQuery = " SELECT CategorySubID, CategorySubName FROM cs_CategorySubList WHERE CategorySubID = '" + catID + "' AND (Flag = 0) AND (Status = 0) AND CategoryID = 1";
            sqlQuery = " SELECT CategorySubID, CategorySubName FROM cs_CategorySubList WHERE CategorySubID = '" + catID + "' AND CategorySubID != 11 AND (Flag = 0) AND (Status = 0) AND CategoryID = 1";
            sqlQuery += " UNION SELECT CategorySubID, CategorySubName FROM cs_CategorySubList WHERE (Flag = 0) AND CategorySubID != 11 AND (Status = 0) AND CategoryID = 1";

            using (SqlConnection conn = new SqlConnection(connection()))
            {
                try
                {
                    SqlCommand cmd = new SqlCommand(sqlQuery, conn);
                    conn.Open();

                    SqlDataAdapter da = new SqlDataAdapter(cmd);
                    DataSet ds = new DataSet();
                    da.Fill(ds);
                    Category.DataSource = ds;
                    Category.DataTextField = "CategorySubName";
                    Category.DataValueField = "CategorySubID";
                    // professionlist.SelectedValue = ProfName;
                    int x = Convert.ToInt32(catID) - 1 ;
                    Category.SelectedIndex = x;
                    Category.DataBind();
                }
                catch (SqlException ex)
                {
                    string msg = "Fetch Error: ";
                    msg += ex.Message;
                    throw new Exception(msg);
                }
                finally
                {
                    conn.Close();
                }
            }
        
        }

on update:

protected void dlPromotionList_UpdateCommand(object source, DataListCommandEventArgs e)
        {
            getSession();
            DateTime date = System.DateTime.Now;
          
            string ID = Convert.ToString(dlPromotionList.DataKeys[e.Item.ItemIndex]);
            String Title = ((TextBox)e.Item.FindControl("PromotionTitle")).Text;
            String Description = ((TextBox)e.Item.FindControl("PromotionDescription")).Text;
            
            String Category = ((DropDownList)e.Item.FindControl("Category")).Text;
            String Url = ((TextBox)e.Item.FindControl("PromotionUrl")).Text;
            String PromotionDeadline= ((TextBox)e.Item.FindControl("PromotionDeadline")).Text;
            String PhotoID = ((Label)e.Item.FindControl("lblPromotionPhoto")).Text;
            FileUpload promotionupload = ((FileUpload)e.Item.FindControl("PromotionPicUpload"));

            FileUpload img = (FileUpload)promotionupload;
            string fileExt = Path.GetExtension(promotionupload.FileName).ToLower();
            string x;
            string fn = "update";
            
            if (img.HasFile && img.PostedFile != null)
            {
                deleteRowPromo(PhotoID);

                if (fileExt != ".gif" || fileExt != ".jpg" || fileExt != ".jpeg" || fileExt != ".png" || fileExt != ".swf" || fileExt != ".bmp")
                {
                    x = country + id + "+" + ipx + "+" + date + "+" + hour;
                    updatePic(img, fileExt, x);
                    savePromotionInformation(fn, ID);
                }
                else
                {
                    string alert = "alert('You can upload only jpg ,jpg,gif,swf,bmp file');";
                    ScriptManager.RegisterStartupScript(this, GetType(), "JScript", alert, true);
                }
            }
            using (SqlConnection con = new SqlConnection(connection()))
            {
                string query = "update ws_Offer set ";
                query += " Name = @Title, Description = @Description, Price = @ActualPrice, PromotionDeadline=@PromotionDeadline, PromotionPrice = @PromotionPrice, Category = @Category, Url = @Url, LastModified=@LastModified, LastModifiedBy=@LastModifiedBy,  LastModifiedFromIP=@LastModifiedFromIP";
                query += " where ID = @ID";
                using (SqlCommand cmd = new SqlCommand(query))
                {
                    cmd.Connection = con;
                    cmd.Parameters.AddWithValue("@Title", Title);
                    cmd.Parameters.AddWithValue("@Description", Description);
                    cmd.Parameters.AddWithValue("@ActualPrice", ActualPrice);
                    cmd.Parameters.AddWithValue("@PromotionPrice", PromotionPrice);
                    cmd.Parameters.AddWithValue("@PromotionDeadline", PromotionDeadline);
                    cmd.Parameters.AddWithValue("@Category", Category);
                    cmd.Parameters.AddWithValue("@Url", Url);
                    cmd.Parameters.AddWithValue("@LastModified", date);
                    cmd.Parameters.AddWithValue("@LastModifiedBy", HiddenGUIDx.Value);
                    cmd.Parameters.AddWithValue("@LastModifiedFromIP", ipx);
                    cmd.Parameters.AddWithValue("@ID", ID);
                    con.Open();
                    cmd.ExecuteNonQuery();
                    con.Close();
                }

            }
            dlPromotionList.EditItemIndex = -1;
            BinddlPromotionList();
        }

Check the id of the control, make sure you type correct control id.

AFAIK, this is  PromotionCategory instead Category

Try this

DropDownList ddlcat=(DropDownList)e.Item.FindControl("PromotionCategory");
String Category = ddlcat.SelectedItem.Text;

Try this:

String Category = ((DropDownList)e.Item.FindControl("Category")).SelectedItem.Text;