From e75a119d4afcabb59c41956b52aafa4bc530f014 Mon Sep 17 00:00:00 2001
From: Edward Miller <symbiogenisis@outlook.com>
Date: Thu, 28 Dec 2023 22:58:35 -0600
Subject: [PATCH] initialize column data type if needed

---
 Maui.DataGrid/DataGrid.xaml.cs  |  2 ++
 Maui.DataGrid/DataGridColumn.cs | 23 +++++++++++++++--------
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/Maui.DataGrid/DataGrid.xaml.cs b/Maui.DataGrid/DataGrid.xaml.cs
index 19c605b..7ac2aa6 100644
--- a/Maui.DataGrid/DataGrid.xaml.cs
+++ b/Maui.DataGrid/DataGrid.xaml.cs
@@ -1285,6 +1285,8 @@ private void InitHeaderView()
         {
             var col = Columns[i];
 
+            col.InitializeDataType();
+
             col.ColumnDefinition ??= new(col.Width);
 
             col.DataGrid ??= this;
diff --git a/Maui.DataGrid/DataGridColumn.cs b/Maui.DataGrid/DataGridColumn.cs
index 5471f27..fac07df 100644
--- a/Maui.DataGrid/DataGridColumn.cs
+++ b/Maui.DataGrid/DataGridColumn.cs
@@ -173,6 +173,8 @@ public event EventHandler SizeChanged
 
     internal SortingOrder SortingOrder { get; set; }
 
+    internal Type? DataType { get; private set; }
+
     internal DataGrid? DataGrid { get; set; }
 
     internal ColumnDefinition? ColumnDefinition
@@ -338,15 +340,9 @@ public bool IsSortable(DataGrid dataGrid)
             {
                 _isSortable = false;
             }
-            else
+            else if (DataType is not null)
             {
-                var listItemType = dataGrid.ItemsSource.GetType().GetGenericArguments().Single();
-                var columnDataType = listItemType.GetProperty(PropertyName)?.PropertyType;
-
-                if (columnDataType is not null)
-                {
-                    _isSortable = typeof(IComparable).IsAssignableFrom(columnDataType);
-                }
+                _isSortable = typeof(IComparable).IsAssignableFrom(DataType);
             }
         }
         catch
@@ -357,6 +353,17 @@ public bool IsSortable(DataGrid dataGrid)
         return _isSortable ??= false;
     }
 
+    internal void InitializeDataType()
+    {
+        ArgumentNullException.ThrowIfNull(DataGrid);
+
+        if (DataType == null && EditCellTemplate == null)
+        {
+            var rowDataType = DataGrid.ItemsSource.GetType().GetGenericArguments().Single();
+            DataType = rowDataType.GetProperty(PropertyName)?.PropertyType;
+        }
+    }
+
     private void OnSizeChanged() => _sizeChangedEventManager.HandleEvent(this, EventArgs.Empty, nameof(SizeChanged));
 
     #endregion Methods