WPFQ&A 200702

Q:
Canves是否支持拖放？
A:
Canves 控件是支持拖放功能的，但是除了要设置canves空间的AllowDrop属性为true外，还要设置一下canves控件的background属性，如果不设置background属性， 这个Canves控件的拖放时没有效果的。

Q:
如何对ListView控件的数据进行排序?

A:
Demo代码如下:

<Grid.Resources>
    <DataTemplate x:Key="HeaderTemplateArrowUp">
      <DockPanel>
        <TextBlock HorizontalAlignment="Center" Text="{Binding}"/>
        <Path x:Name="arrow"
           StrokeThickness = "1"                     
           Fill            = "gray"
           Data            = "M 5,10 L 15,10 L 10,5 L 5,10"/>
      </DockPanel>
    </DataTemplate>
    <DataTemplate x:Key="HeaderTemplateArrowDown">
      <DockPanel>
        <TextBlock HorizontalAlignment="Center" Text="{Binding }"/>
        <Path x:Name="arrow"
              StrokeThickness = "1"                  
              Fill            = "gray"
              Data            = "M 5,5 L 10,10 L 15,5 L 5,5"/>
      </DockPanel>
    </DataTemplate>
 </Grid.Resources>
<ListView BorderBrush="Gray" x:Name="prtyList" 
 GridViewColumnHeader.Click="GridViewColumnHeaderClickedHandler">
              <ListView.ContextMenu>
                <ContextMenu>
                  <MenuItem Name ="ctmAddPro" Header ="添加属性" Click ="ctmAddPro_Click" />
                  <MenuItem Name ="ctmModifyPro" Header ="修改属性" Click="ctmModifyPro_Click"/>
                  <MenuItem Name ="ctmDeletePro" Header ="删除属性" Click="ctmDeletePro_Click"/>
                </ContextMenu>
              </ListView.ContextMenu>
              <ListView.View>
                <GridView>
                  <GridViewColumn Header="属性中文名" Width="150" x:Name="prtyName"/>
                  <GridViewColumn Header="属性英文名" Width="150" x:Name="prtyAliasName"/>
                  <GridViewColumn Header="属性组" Width="150" x:Name="prtyGroup"/>
                  <GridViewColumn Header="属性类型" Width="120" x:Name="prtyType"/>
                  <GridViewColumn Header="属性值类型" Width="90" x:Name="prtyVType"/>
                  <GridViewColumn Header="非空" Width="90" x:Name="prtyNotNull"/>
                  <GridViewColumn Header="主键属性" Width="90" x:Name="prtyKey"/>
                  <GridViewColumn Header="继承自超类" Width="90" x:Name="prtyInherit"/>
                  <GridViewColumn Header="默认值" Width="90" x:Name="prtyDefault"/>
                  <GridViewColumn Header="长度" Width="90" x:Name="prtyLength"/>
                  <GridViewColumn Header="备注" Width="150" x:Name="prtyRemark"/>
                </GridView>
              </ListView.View>
            </ListView>

private void GridViewColumnHeaderClickedHandler(object sender, RoutedEventArgs e)
        {
            GridViewColumnHeader headerClicked = e.OriginalSource as GridViewColumnHeader;
            ListSortDirection direction;
 
            if (headerClicked != null)
            {
                if (headerClicked.Role != GridViewColumnHeaderRole.Padding)
                {
                    if (headerClicked != _lastHeaderClicked)
                    {
                        direction = ListSortDirection.Ascending;
                    }
                    else
                    {
                        if (_lastDirection == ListSortDirection.Ascending)
                        {
                            direction = ListSortDirection.Descending;
                        }
                        else
                        {
                            direction = ListSortDirection.Ascending;
                        }
                    }
                    string header = headerClicked.Column.Header as string;
                    Sort(header, direction);

                    if (direction == ListSortDirection.Ascending)
                    {
                        headerClicked.Column.HeaderTemplate =
                          Resources["HeaderTemplateArrowUp"] as DataTemplate;
                    }
                    else
                    {
                        headerClicked.Column.HeaderTemplate =
                          Resources["HeaderTemplateArrowDown"] as DataTemplate;
                    }
                    _lastHeaderClicked = headerClicked;
                    _lastDirection = direction;
                }
            }
        }

        private void Sort(string sortBy, ListSortDirection direction)
        {
            ICollectionView dataView =
              CollectionViewSource.GetDefaultView(prtyList.ItemsSource);
            dataView.SortDescriptions.Clear();
            SortDescription sd = new SortDescription(sortBy, direction);
            dataView.SortDescriptions.Add(sd);
            dataView.Refresh();
        }

Q:
如何在xaml里使用资源？
A:

xmlns:resource="clr-namespace:OssWise.ConceptModel.Editor.Properties"

Icon="{x:Static　resource:Resources.logolittle}"