无法为DataTemplate Tooltip设置父datacontext。
以下是XAML代码。仅一次组合框,然后在Commobox DatateMplate中添加了文本框。
XAML
<UserControl x:Class="WpfApplication1.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
Name="UC"
d:DesignHeight="50" d:DesignWidth="200">
<Grid>
<ComboBox Width="200" Height="50" ItemsSource="{Binding Coll}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Length}">
<TextBlock.ToolTip>
<ToolTip Content="{Binding Path=DataContext.ToolTipValue,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type UserControl}}}"/>
</TextBlock.ToolTip>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</Grid>
</UserControl>
ViewModel
private List<string> _coll;
public List<string> Coll
{
get { return _coll; }
set { _coll = value; OnPropertyChanged(); }
}
private string _ToolTipValue;
public string ToolTipValue
{
get { return _ToolTipValue; }
set { _ToolTipValue = value; OnPropertyChanged(); }
}
public ViewModel()
{
_coll = new List<string>(){ "1", "2", "3"};
_ToolTipValue = "Demo";
}
您可以帮助我为什么未设置DataContext。
它是绑定的问题吗?
如果您不需要任何特殊的东西,请不要嵌套工具提示:
<TextBlock ToolTip="{Binding DataContext.ToolTipValue,
RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}}"
Text="{Binding Length}"/>