数字键盘加负号

WinFormControl/NumberPad.xaml

@@ -50,10 +50,11 @@
     <Button Grid.Row="2" Grid.Column="0"  x:Name="button9" CommandParameter="NUMPAD4"  Content="4"/>
     <Button Grid.Row="2" Grid.Column="1" CommandParameter="NUMPAD5" Content="5" />
     <Button Grid.Row="2" Grid.Column="2" CommandParameter="NUMPAD6" Content="6" />
+    <Button Grid.Row="2" Grid.Column="3" CommandParameter="NUMPAD-" Content="-" />
     <Button Grid.Row="3" Grid.Column="0" CommandParameter="NUMPAD1" Content="1"/>
     <Button Grid.Row="3" Grid.Column="1" CommandParameter="NUMPAD2" Content="2"/>
     <Button Grid.Row="3" Grid.Column="2" CommandParameter="NUMPAD3" Content="3" />
-    <Button Grid.Row="2" Grid.Column="3" Grid.RowSpan="3" CommandParameter="RETURN" Content="Enter"/>
+    <Button Grid.Row="3" Grid.Column="3" Grid.RowSpan="2" CommandParameter="RETURN" Content="Enter"/>
     <Button Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="2"  CommandParameter="NUMPAD0" Content="0" />
     <Button Grid.Row="4" Grid.Column="2" CommandParameter="DECIMAL"	Content="." />
     <Label Grid.Column="0" Grid.ColumnSpan="4"  Content="{Binding Result}" HorizontalContentAlignment="Right" Background="WhiteSmoke" Margin="4"/>