feat:

LoginWindow.xaml

@@ -66,7 +66,7 @@
                             <Image Grid.Column="0" Width="25" Height="25" Source="Resource/Images/UIResource/08-2.png" />
                             <hc:TextBox Grid.Column="1"  Grid.ColumnSpan="2"  BorderThickness="0" FontSize="18" HorizontalAlignment="Stretch" 
                                        Background="Transparent" Padding="5 0" hc:InfoElement.ShowClearButton="True"
-                                       VerticalAlignment="Stretch" TextAlignment="Left" x:Name="AccountTextBox"
+                                       VerticalAlignment="Stretch" TextAlignment="Left" x:Name="AccountTextBox" MaxLength="20"
                                        hc:InfoElement.Placeholder="{StaticResource LoginWindowAccount}" 
                             />
                             <!-- <Image Grid.Column="2" Width="25" Height="25" Source="Resource/Images/UIResource/08-4.png" MouseLeftButtonDown="UIElement_OnMouseLeftButtonDown"  /> -->
@@ -87,6 +87,7 @@
                             <Image Grid.Column="0" Width="25" Height="25" Source="Resource/Images/UIResource/08-3.png" />
                             <hc:PasswordBox Grid.Column="1" Grid.ColumnSpan="2" ShowEyeButton="True"   BorderThickness="0" x:Name="PasswordBox"
                                             FontSize="18" HorizontalAlignment="Stretch" hc:InfoElement.Necessary="True"   Background="Transparent" 
+                                            MaxLength="20"
                                             hc:InfoElement.Placeholder="{StaticResource LoginWindowPassword}" />
                             
                         </Grid>