[WinForms] fix EditingCellFormattedValue getter and setter for bool value (#13845)

* [WinForms] If DataGridViewCheckBoxCell not in threeState mode
EditingCellFormattedValue must return true or false, instead of
value of CheckState type

* [WinForms] DataGrid: fix type check in EditingCellFormattedValue setter.
When set bool value to EditingCellFormattedValue there will be exception.
Type equality must be done through IsAssignableFrom not direct

* [WinForms] DataGrid: Add test for EditingCellFormattedValue getter and setter.

2 files changed, 38 insertions, 3 deletions

diff --git a/mcs/class/System.Windows.Forms/System.Windows.Forms/DataGridViewCheckBoxCell.cs b/mcs/class/System.Windows.Forms/System.Windows.Forms/DataGridViewCheckBoxCell.cs
index 6ef788eff1f..c88624de5c6 100644
--- a/mcs/class/System.Windows.Forms/System.Windows.Forms/DataGridViewCheckBoxCell.cs
+++ b/mcs/class/System.Windows.Forms/System.Windows.Forms/DataGridViewCheckBoxCell.cs
@@ -59,13 +59,14 @@ namespace System.Windows.Forms {
 		public DataGridViewCheckBoxCell (bool threeState) : this()
 		{
 			this.threeState = threeState;
-			editingCellFormattedValue = CheckState.Unchecked;
+			if (threeState)
+				editingCellFormattedValue = CheckState.Unchecked;
 		}
 
 		public virtual object EditingCellFormattedValue {
 			get { return editingCellFormattedValue; }
 			set {
-				if (FormattedValueType == null || value == null || value.GetType() != FormattedValueType || !(value is Boolean) || !(value is CheckState)) {
+				if (FormattedValueType == null || value == null || !FormattedValueType.IsAssignableFrom(value.GetType())) {
 					throw new ArgumentException("Cannot set this property.");
 				}
 				editingCellFormattedValue = value;
@@ -192,7 +193,11 @@ namespace System.Windows.Forms {
 
 		public virtual void PrepareEditingCellForEdit (bool selectAll)
 		{
-			editingCellFormattedValue = GetCurrentValue ();
+			CheckState cs = GetCurrentValue();
+			if (threeState)
+				editingCellFormattedValue = cs;
+			else
+				editingCellFormattedValue = cs == CheckState.Checked;
 		}
 
 		public override string ToString ()
diff --git a/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/DataGridViewCheckBoxCellTest.cs b/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/DataGridViewCheckBoxCellTest.cs
index 7b2f090038c..1ad4e69ef24 100644
--- a/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/DataGridViewCheckBoxCellTest.cs
+++ b/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/DataGridViewCheckBoxCellTest.cs
@@ -200,6 +200,36 @@ namespace MonoTests.System.Windows.Forms
 		}
 
 		[Test]
+		public void EditingCellFormattedValue()
+		{
+			var boolCheckBoxCell = new DataGridViewCheckBoxCell();
+			Assert.AreEqual(false, boolCheckBoxCell.EditingCellFormattedValue, "A1");
+			boolCheckBoxCell.EditingCellFormattedValue = true;
+			Assert.AreEqual(true, boolCheckBoxCell.EditingCellFormattedValue, "A2");
+
+			var treeStateCheckBoxCell = new DataGridViewCheckBoxCell(true);
+			Assert.AreEqual(CheckState.Unchecked, treeStateCheckBoxCell.EditingCellFormattedValue, "A3");
+			treeStateCheckBoxCell.EditingCellFormattedValue = CheckState.Checked;
+			Assert.AreEqual(CheckState.Checked, treeStateCheckBoxCell.EditingCellFormattedValue, "A4");
+		}
+
+		[Test]
+		[ExpectedException(typeof(ArgumentException))]
+		public void BoolEditingCellFormattedValueCheckStateSet()
+		{
+			var boolCheckBoxCell = new DataGridViewCheckBoxCell();
+			boolCheckBoxCell.EditingCellFormattedValue = CheckState.Checked;
+		}
+
+		[Test]
+		[ExpectedException(typeof(ArgumentException))]
+		public void TreeStateEditingCellFormattedValueBoolSet()
+		{
+			var treeStateCheckBoxCell = new DataGridViewCheckBoxCell(true);
+			treeStateCheckBoxCell.EditingCellFormattedValue = false;
+		}
+
+		[Test]
 		public void FormattedValueType ()
 		{
 			BaseCell c = new BaseCell ();