如何根据WPF中ListBox的高度显示项目？

1 回答

• 3

  听起来像 UniformGrid 的完美用例：

  <ListBox.ItemsPanel>
      <ItemsPanelTemplate>
          <UniformGrid Columns="4"/>
      </ItemsPanelTemplate>
  </ListBox.ItemsPanel>
  

  预期结果：

  

  使用略微修改的UniformGrid（取自this MSDN question）可以实现垂直方向：

  public class UniformGridWithOrientation : UniformGrid  
  {
      public static readonly DependencyProperty OrientationProperty =  
          DependencyProperty.Register( "Orientation", typeof( System.Windows.Controls.Orientation ), typeof( UniformGridWithOrientation ),  
              new FrameworkPropertyMetadata(   
                  System.Windows.Controls.Orientation.Vertical,   
                  FrameworkPropertyMetadataOptions.AffectsMeasure ),    
              new ValidateValueCallback( UniformGridWithOrientation.IsValidOrientation ) );  
  
      internal static bool IsValidOrientation( object o )  
      {  
          System.Windows.Controls.Orientation orientation = (System.Windows.Controls.Orientation)o;  
          if( orientation != System.Windows.Controls.Orientation.Horizontal )  
          {  
              return ( orientation == System.Windows.Controls.Orientation.Vertical );  
          }  
          return true;  
      }  
  
      public System.Windows.Controls.Orientation Orientation  
      {  
          get { return (System.Windows.Controls.Orientation)GetValue( OrientationProperty ); }  
          set { SetValue( OrientationProperty, value ); }  
      }
  
      private int _columns;  
      private int _rows;  
  
      protected override Size MeasureOverride( Size constraint )  
      {  
          this.UpdateComputedValues();  
          Size availableSize = new Size( constraint.Width / ( (double)this._columns ), constraint.Height / ( (double)this._rows ) );  
          double width = 0.0;  
          double height = 0.0;  
          int num3 = 0;  
          int count = base.InternalChildren.Count;  
          while( num3 < count )  
          {  
              UIElement element = base.InternalChildren[ num3 ];  
              element.Measure( availableSize );  
              Size desiredSize = element.DesiredSize;  
              if( width < desiredSize.Width )  
              {  
                  width = desiredSize.Width;  
              }  
              if( height < desiredSize.Height )  
              {  
                  height = desiredSize.Height;  
              }  
              num3++;  
          }  
          return new Size( width * this._columns, height * this._rows );  
      }  
  
      private void UpdateComputedValues()  
      {  
          this._columns = this.Columns;  
          this._rows = this.Rows;  
          if( this.FirstColumn >= this._columns )  
          {  
              this.FirstColumn = 0;  
          }  
  
          if( FirstColumn > 0 )  
              throw new NotImplementedException( "There is no support for seting the FirstColumn (nor the FirstRow)." );  
          if( ( this._rows == 0 ) || ( this._columns == 0 ) )  
          {  
              int num = 0;    // Visible children  
              int num2 = 0;  
              int count = base.InternalChildren.Count;  
              while( num2 < count )  
              {  
                  UIElement element = base.InternalChildren[ num2 ];  
                  if( element.Visibility != Visibility.Collapsed )  
                  {  
                      num++;  
                  }  
                  num2++;  
              }  
              if( num == 0 )  
              {  
                  num = 1;  
              }  
              if( this._rows == 0 )  
              {  
                  if( this._columns > 0 )  
                  {  
                      this._rows = ( ( num + this.FirstColumn ) + ( this._columns - 1 ) ) / this._columns;  
                  }  
                  else 
                  {  
                      this._rows = (int)Math.Sqrt( (double)num );  
                      if( ( this._rows * this._rows ) < num )  
                      {  
                          this._rows++;  
                      }  
                      this._columns = this._rows;  
                  }  
              }  
              else if( this._columns == 0 )  
              {  
                  this._columns = ( num + ( this._rows - 1 ) ) / this._rows;  
              }  
          }  
      }  
  
      protected override Size ArrangeOverride( Size arrangeSize )  
      {  
          Rect finalRect = new Rect( 0.0, 0.0, arrangeSize.Width / ( (double)this._columns ), arrangeSize.Height / ( (double)this._rows ) );  
          double height = finalRect.Height;  
          double numX = arrangeSize.Height - 1.0;  
          finalRect.X += finalRect.Width * this.FirstColumn;  
          foreach( UIElement element in base.InternalChildren )  
          {  
              element.Arrange( finalRect );  
              if( element.Visibility != Visibility.Collapsed )  
              {  
                  finalRect.Y += height;  
                  if( finalRect.Y >= numX )  
                  {  
                      finalRect.X += finalRect.Width;  
                      finalRect.Y = 0.0;  
                  }  
              }  
          }  
          return arrangeSize;  
      }  
  }
  

  设置 Orientation="Vertical" 时的结果：

  

  回复于 2024-04-23T19:54:40+08:00