WPF - Tips & Tricks (July 2020)

Here’s this month’s edition of WPF Tips & Tricks.

Should you have questions regarding the support tickets referenced in this post, feel free to comment below. We’ll be happy to follow-up.

Data Grid

• How to display multiline text in the WPF Grid control’s header (T906783)
• How to prevent the expansion of the first group when the WPF Grid Control is bound to CollectionView (T906810)
• How to specify custom items for the ExcelSmart filter popup (T914991)

  One way to customize a column’s filter dropdown is to subscribe to its TableView’s  ShowFilterPopup event. You can also handle this event to modify its Excel-style drop-down filter as follows:
  
  
  

• How to highlight Grid Control cells based on values in a dictionary (T906148)
  

  Conditional Formatting includes a large number of built-in function operators. It also allows you to create your own custom function operators for specific usage scenarios:

  public class IsInDirtyDictionary : ICustomFunctionOperator {
      public object Evaluate(params object[] operands) {
          if (operands[1] is Dictionary<string, bool>
              && operands[0] != null
              && ((Dictionary<string, bool>)operands[1]).ContainsKey(operands[0].ToString())) {
              return ((Dictionary<string, bool>)operands[1])[operands[0].ToString()];
          }
          return false;
      }
  
      public string Name {
          get { return "IsInDirtyDictionary"; }
      }
  
      public Type ResultType(params Type[] operands) {
          return typeof(bool);
      }
  }
  

  public MainWindow() {
  	InitializeComponent();
  	CriteriaOperator.RegisterCustomFunction(new IsInDirtyDictionary());
  }
  

  <dxg:FormatCondition Expression="IsInDirtyDictionary('Name', [Dirty])" FieldName="Name">
    <dxg:FormatCondition.Format>
      <dx:Format Background="Red" />
    </dxg:FormatCondition.Format>
  </dxg:FormatCondition>
  

   
•  WPF Grid Control – pasting more than 242 columns (T913311)

Tree List

• How to display items from different collections as children for the same parent node (T905175)
• How to draw horizontal lines between nodes at different levels (T906515)
• How to hide seconds in DateEdit with DateEditNavigatorWithTimePickerStyleSettings (T833668)
  

  If using v20.1, use our built-in TimePicker.VisibleMaskParts property to configure visible mask segments.
  

  <Window.Resources>
      <Style TargetType="dxe:TimePicker">
          <Setter Property="VisibleMaskParts" Value="Hours,Minutes" />
      </Style>
  </Window.Resources>
  

Editors

• How to use AutoSuggestEdit as a cell editor in a column bound to a complex property type (T904440)
• How to implement an editor from TimePicker without the clock (T905936)
• How to disable drop-down items in ComboBoxEdit with RadioComboBoxStyleSettings (T913330)
  

  To customize drop-down items (when you’ve set the StyleSettings property), use the StyleSettings.ItemContainerStyle property. Please note that your custom style must inherit built-in item styles as follows:

  <dxe:ComboBoxEdit.StyleSettings>
      <dxe:RadioComboBoxStyleSettings>
          <dxe:RadioComboBoxStyleSettings.ItemContainerStyle>
              <Style xmlns:dxet="http://schemas.devexpress.com/winfx/2008/xaml/editors/themekeys"
                     BasedOn="{StaticResource {dxet:EditorListBoxThemeKey ResourceKey=RadioButtonItemStyle}}"
                     TargetType="{x:Type dxe:ComboBoxEditItem}">
  
              </Style>
          </dxe:RadioComboBoxStyleSettings.ItemContainerStyle>
      </dxe:RadioComboBoxStyleSettings>
  </dxe:ComboBoxEdit.StyleSettings>
  

• How to use FilterEditorControl in standalone mode without a data control - with a filtering context (T913671)

Other Controls

• How to change date display format in Month View cells (T906412)
  

  MonthCellControl visualizes a Month View cell. It includes a set of properties designed to specify a custom display format for dates displayed within cells. Use a custom CellStyle to specify these properties in your Scheduler control.

  <dxsch:MonthView.CellStyle>
      <Style TargetType="dxschv:MonthCellControl">
          <Setter Property="DayStringFormat" Value="{}{0:MM/dd}"/>
          <Setter Property="FirstDayOfMonthStringFormat" Value="{}{0:MM/dd}"/>
          <Setter Property="FirstDayOfYearStringFormat" Value="{}{0:MM/dd}"/>
      </Style>
  </dxsch:MonthView.CellStyle>
  

• How to align the title and description in our WPF Property Grid control's Description Panel (T915080)

• Axis Labels - How to change the first custom axis label font style to Bold  (T906921)

If you’ve come across a WPF-related support ticket you’d like to share with the rest of the DevExpress community, feel free to share the link in the comments section.