Index: Core/Common/src/Core.Common.Controls/DataGrid/DataGridViewControlCellFormatExtensions.cs
===================================================================
diff -u -r6cdb90fc3f89fe0c44b62d3be7266a0090a6b891 -rbcaba4c27e18f3551487c131816fb5c01eff0f32
--- Core/Common/src/Core.Common.Controls/DataGrid/DataGridViewControlCellFormatExtensions.cs	(.../DataGridViewControlCellFormatExtensions.cs)	(revision 6cdb90fc3f89fe0c44b62d3be7266a0090a6b891)
+++ Core/Common/src/Core.Common.Controls/DataGrid/DataGridViewControlCellFormatExtensions.cs	(.../DataGridViewControlCellFormatExtensions.cs)	(revision bcaba4c27e18f3551487c131816fb5c01eff0f32)
@@ -39,14 +39,20 @@
         /// is <c>null</c>.</exception>
         /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="rowIndex"/>
         /// or the <paramref name="columnIndex"/> does not exist.</exception>
+        /// <remarks>When the <see cref="DataGridViewRow.DataBoundItem"/> of the corresponding row is not of
+        /// the type <see cref="IHasColumnStateDefinitions"/>, no formatting is applied.</remarks>
         public static void FormatCellWithColumnStateDefinition(this DataGridViewControl dataGridViewControl, int rowIndex, int columnIndex)
         {
             if (dataGridViewControl == null)
             {
                 throw new ArgumentNullException(nameof(dataGridViewControl));
             }
 
-            var row = (IHasColumnStateDefinitions) dataGridViewControl.GetRowFromIndex(rowIndex).DataBoundItem;
+            if (!(dataGridViewControl.GetRowFromIndex(rowIndex).DataBoundItem is IHasColumnStateDefinitions row))
+            {
+                return;
+            }
+
             if (row.ColumnStateDefinitions.ContainsKey(columnIndex))
             {
                 DataGridViewColumnStateDefinition columnStateDefinition = row.ColumnStateDefinitions[columnIndex];
Index: Core/Common/test/Core.Common.Controls.Test/DataGrid/DataGridViewControlCellFormatExtensionsTest.cs
===================================================================
diff -u -r51b64230b9b947ba32821ed104809429d469959b -rbcaba4c27e18f3551487c131816fb5c01eff0f32
--- Core/Common/test/Core.Common.Controls.Test/DataGrid/DataGridViewControlCellFormatExtensionsTest.cs	(.../DataGridViewControlCellFormatExtensionsTest.cs)	(revision 51b64230b9b947ba32821ed104809429d469959b)
+++ Core/Common/test/Core.Common.Controls.Test/DataGrid/DataGridViewControlCellFormatExtensionsTest.cs	(.../DataGridViewControlCellFormatExtensionsTest.cs)	(revision bcaba4c27e18f3551487c131816fb5c01eff0f32)
@@ -44,14 +44,38 @@
         public void FormatCellWithColumnStateDefinition_DataGridViewControlNull_ThrowsArgumentNullException()
         {
             // Call
-            TestDelegate call = () => ((DataGridViewControl) null).FormatCellWithColumnStateDefinition(0, 0);
+            void Call() => ((DataGridViewControl) null).FormatCellWithColumnStateDefinition(0, 0);
 
             // Assert
-            var exception = Assert.Throws<ArgumentNullException>(call);
+            var exception = Assert.Throws<ArgumentNullException>(Call);
             Assert.AreEqual("dataGridViewControl", exception.ParamName);
         }
 
         [Test]
+        public void FormatCellWithColumnStateDefinition_RowWithoutColumnStateDefinitions_DoesNotThrow()
+        {
+            // Setup
+            using (var form = new Form())
+            using (var dataGridViewControl = new DataGridViewControl())
+            {
+                form.Controls.Add(dataGridViewControl);
+                form.Show();
+
+                dataGridViewControl.AddTextBoxColumn(null, "Test");
+                dataGridViewControl.SetDataSource(new[]
+                {
+                    new object()
+                });
+
+                // Call
+                void Call() => dataGridViewControl.FormatCellWithColumnStateDefinition(0, 0);
+
+                // Assert
+                Assert.DoesNotThrow(Call);
+            }
+        }
+
+        [Test]
         [TestCaseSource(nameof(CellFormattingStates))]
         public void FormatCellWithColumnStateDefinition_WithArguments_FormatsCell(
             bool isReadOnly, string errorText, CellStyle cellStyle)
@@ -95,6 +119,8 @@
                 Assert.AreEqual(errorText, cell.ErrorText);
                 Assert.AreEqual(cellStyle.BackgroundColor, cell.Style.BackColor);
                 Assert.AreEqual(cellStyle.TextColor, cell.Style.ForeColor);
+
+                mocks.VerifyAll();
             }
         }
     }