Question

我在MultiBinding上使用MultiValueConverter和Grid，以便根据MaxHeight设置每个Grid.Row的{{1}}所有ActualHeight s。

Grid.Row

多转换：

               <RowDefinition x:Name="grdRow1" Height="Auto" >
                    <RowDefinition.MaxHeight>
                        <MultiBinding Converter="{StaticResource CalculateMaxHeightConverter}" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
                            <Binding Path="ActualHeight" ElementName="grdRow1" />
                            <Binding Path="ActualHeight" ElementName="grdRow2" />
                            <Binding Path="ActualHeight" ElementName="grdRow3" />
                            <Binding Path="ActualHeight" ElementName="grdRow4" />
                            <Binding Path="ActualHeight" ElementName="grdRow5" /> 
                        </MultiBinding>
                    </RowDefinition.MaxHeight>
                </RowDefinition>

UserControl.Resources：

public class AvailableHeightConverter : IMultiValueConverter
{
    public double PanelHeight { get; set; }

    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        if (values == null)
            return Binding.DoNothing;

        double currentHeight = 0d;
        double availableHeight = 0d;

        foreach (object value in values)
        {
            currentHeight += (double)value;
        }

        availableHeight = PanelHeight - currentHeight;

        if (availableHeight < 0)
            return Binding.DoNothing;

        return availableHeight;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

我的问题（一个假的问题）是，当<cvc:AvailableHeightConverter x:Key="CalculateMaxHeightConverter" PanelHeight="1080" />的{{1}}被更改时，我无法弄明白UpdateSourceTrigger的方式。

Answer 1

你的xaml有两个问题（据我所知，我自己没有尝试过）

ActualHeight没有setter，因此您需要使用Mode =“OneWay”
将grdRow1的MaxHeight绑定到所有行ActualHeight包括grdRow1本身可能会产生无限循环的大小调整

尝试以下方法：

            <RowDefinition x:Name="grdRow1" Height="Auto" >
                <RowDefinition.MaxHeight>
                    <MultiBinding Converter="{StaticResource CalculateMaxHeightConverter}" Mode="OneWay" UpdateSourceTrigger="PropertyChanged">
                        <Binding Path="ActualHeight" ElementName="grdRow2" Mode="OneWay" />
                        <Binding Path="ActualHeight" ElementName="grdRow3" Mode="OneWay" />
                        <Binding Path="ActualHeight" ElementName="grdRow4" Mode="OneWay" />
                        <Binding Path="ActualHeight" ElementName="grdRow5" Mode="OneWay" /> 
                    </MultiBinding>
                </RowDefinition.MaxHeight>
            </RowDefinition>

Answer 2

行。在尝试各种senarios后，我最终Binding行ActualHeight没有通知MultiBinding更改。 @christoph注意到（2.）也非常有帮助。所以我最终绑定了TextBox＆＃39; ActualWidth，如下所示：

第1行的

            <RowDefinition x:Name="grdRow1" Height="Auto" >
            <RowDefinition.MaxHeight>
                <MultiBinding Converter="{StaticResource CalculateMaxHeightConverter}">
                    <Binding Path="ActualHeight" ElementName="txtBox2" Mode="OneWay" />
                    <Binding Path="ActualHeight" ElementName="txtBox3" Mode="OneWay" />
                    <Binding Path="ActualHeight" ElementName="txtBox4" Mode="OneWay" />
                    <Binding Path="ActualHeight" ElementName="txtBox5" Mode="OneWay" /> 
                </MultiBinding>
            </RowDefinition.MaxHeight>
        </RowDefinition>

第2行的

        <RowDefinition x:Name="grdRow2" Height="Auto" >
            <RowDefinition.MaxHeight>
                <MultiBinding Converter="{StaticResource CalculateMaxHeightConverter}">
                    <Binding Path="ActualHeight" ElementName="txtBox1" Mode="OneWay" />
                    <Binding Path="ActualHeight" ElementName="txtBox3" Mode="OneWay" />
                    <Binding Path="ActualHeight" ElementName="txtBox4" Mode="OneWay" />
                    <Binding Path="ActualHeight" ElementName="txtBox5" Mode="OneWay" /> 
                </MultiBinding>
            </RowDefinition.MaxHeight>
        </RowDefinition>

并从Height（PanelHeight）中减去一行的AvailableHeightConverter。

<cvc:AvailableHeightConverter x:Key="CalculateMaxHeightConverter" PanelHeight="1028" />

（曾经是1080（-52 MinHeight行）

Grid.Row动态调整大小

2 个答案: