Why does my Xamarin.Forms.DataGrid not displaying any data?

Question

Hi everyone,

My datagrid is not displaying any data in my datagrid
I belief it is a binding issue which I'm overlooking.

Here is my xaml code:


                    
                        
                            

                            
                                RetainElement
                            
                            
                                
                                
                                
                                
                                
                                
                                
                                
                                
                                
                                
                            
                            
                                
                                    #E0E6f8

Here is my Model Code

public class DgvItemDetails
    {
        public int DocEntryItemDetails { get; set; }
        public int DocNumItemDetails { get; set; }
        public string ItemCodeItemDetails { get; set; }
        public decimal OpenQtyItemDetails { get; set; }
        public string UomCodeItemDetails { get; set; }
        public DateTime DocDateItemDetails { get; set; }
        public string U_DRTItemDetails { get; set; }
        public decimal Weight1ItemDetails { get; set; }
        public decimal QuantityItemDetails { get; set; }
        public decimal PriceItemDetails { get; set; }
        public string U_PACItemDetails { get; set; }
    }

Here is my ViewModel Code

public ObservableCollection BuildItemDetailsData { get; set; } = new ObservableCollection();

private void GetSQLFillOrderDetails()
        {
            string Customer = string.Empty;

            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();

                if (selectedCustomer != "")
                {
                    string[] CustomerName = selectedCustomer.Split(':');
                    Customer = CustomerName[0];
                }

                try
                {
                    string[] OrderNr;
                    OrderNr = selectedSalesOrder.Split(':');
                    string SQLCommand = @"SELECT rdl.DocEntry AS [Doc Entry], CAST(" + OrderNr[0].Trim() + " AS int) AS [Doc Number]," +
                        "rdl.ItemCode AS [Item Number], rdl.OpenQty AS [Open Quantity], rdl.UomCode as [Unit of Measurement], " +
                        "cast(rdl.DocDate AS date) AS [Order Date], ISNULL(U_DRT,'') AS [Order Time], rdl.Weight1 AS [Weight], " +
                        "rdl.Quantity AS [Original Order Quantity], " +
                        "rdl.Price AS [Price], " +
                        "ISNULL(rdl.U_PAC,'') AS [Packing] " +
                        "FROM RDR1 rdl " +
                        "INNER JOIN ORDR ord ON(ord.DocEntry = rdl.DocEntry) " +
                        "WHERE rdl.LineStatus <> 'C' AND ord.CardCode = '" +
                        Customer + "' AND ord.DocEntry = '" + DocEntrySelected + "'";

                    using (SqlCommand command = new SqlCommand(SQLCommand, connection))
                    {
                        using (SqlDataReader reader = command.ExecuteReader())
                        {
                            if (reader != null)
                            {
                                while (reader.Read())
                                {
                                    BuildItemDetailsData.Add(new DgvItemDetails()
                                    {
                                        DocEntryItemDetails = reader.GetInt32(0),
                                        DocNumItemDetails = reader.GetInt32(1),
                                        ItemCodeItemDetails = reader.GetString(2),
                                        OpenQtyItemDetails = reader.GetDecimal(3),
                                        UomCodeItemDetails = reader.GetString(4),
                                        DocDateItemDetails = reader.GetDateTime(5),
                                        U_DRTItemDetails = reader.GetString(6),
                                        Weight1ItemDetails = reader.GetDecimal(7),
                                        QuantityItemDetails = reader.GetDecimal(8),
                                        PriceItemDetails = reader.GetDecimal(9),
                                        U_PACItemDetails = reader.GetString(10)
                                    });
                                }
                                Application.Current.MainPage.BindingContext = BuildItemDetailsData;
                            }
                        }
                    }
                }
                catch (Exception ex)
                {
                    Application.Current.MainPage.DisplayAlert("Alert", "Error Creating order item list table :", ex.Message);
                }
                connection.Close();
            }
        }

Any help would be appreciated

Answer

Hello,

Welcome to our Microsoft Q&A platform!

This issue is related to Application.Current.MainPage.BindingContext = BuildItemDetailsData; line.

GetSQLFillOrderDetails method in the viewmodel. Please do not bindingContext in the viewmodel. Please remove it and make sure BuildItemDetailsData have items.

And your Xamarin.Forms.DataGrid is in a ContentView. Do you want to use this ContentView in the MainPage? If so, please remove bindingContext code to the MainPage's background code or Compiled Bindings.

Background code.

   public partial class MainPage : ContentPage  
       {  
           public MainPage()  
           {  
               InitializeComponent();  
     
               BindingContext = new MyWiewModel();  
           }  
       }

Or using Compiled Bindings

If you want to know more details about MVVM. There are lots of good docs on MVVM.

MVVM is in the Xaml Basics docs (including a sample)
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/xaml/xaml-basics/data-bindings-to-mvvm

And in learning modules:
https://learn.microsoft.com/en-us/learn/modules/design-a-mvvm-viewmodel-for-xamarin-forms/

As well as in (old, but conceptually still valid) books:
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/enterprise-application-patterns/mvvm

If you still do not know how to change your code. I can give you simple code completely .

Best Regards,

Leon Lu

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Why does my Xamarin.Forms.DataGrid not displaying any data?

1 answer