根据行元素值，控制单元格菜单是否显示

在实际应用中我们经常需要针对不同的内容显示不同的菜单项，这里将解决方式总结记录下：

实现的目的是：当行元素 “Mandatory” 的取值为 “H” 的时候，显示菜单项 “DB Owner” 和 “Table Name”,取其他值的时候则不显示这两个菜单项。（其他判断条件可以采用类似的方式处理）

解决方式： 设置 BarButtonItem 的 “ IsVisible ” 属性值

实现方式：

1. 通过数据绑定的方式实现：

<dxb:BarButtonItem Content="Table Name" IsVisible="{Binding Row.Row.Mandatory,Converter={StaticResource string2BoolConverter}}"
                   Command="{Binding Path=(dxg:DataControlBase.ActiveView).DataContext.SetTableDataHeaderCommand, RelativeSource={RelativeSource Self}}"
           CommandParameter="{Binding ElementName=tvTable, Path=FocusedRowHandle}">
</dxb:BarButtonItem>

注意这里需要使用一个 Converter, 将 Mandatory的字符串取值转换为 “ IsVisible ” 布尔值返回

转换器代码如下：

public class String2BoolConverter : BaseValueConverter
    {
        public override object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (!(value is string))
                return null;
            if (value.ToString() == "H")
                return true;
            if (value.ToString() == "Y" || value.ToString() == "N")
                return false;
            return null;
        }

        public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new System.NotImplementedException();
        }
    }
    public abstract class BaseValueConverter : MarkupExtension, IValueConverter
    {
        public abstract object Convert(object value, Type targetType, object parameter, CultureInfo culture);
        public virtual object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }

        public sealed override object ProvideValue(IServiceProvider serviceProvider)
        {
            return this;
        }
    }

2. 通过 DataTrigger 的方式实现

<Style x:Key="barButtonItemStyle" TargetType="dxb:BarButtonItem">
    <Style.Triggers>
        <DataTrigger Binding="{Binding Row.Row.Mandatory,Converter={StaticResource string2BoolConverter}}" Value="false">
            <Setter Property="IsVisible" Value="False"/>
        </DataTrigger>
    </Style.Triggers>
</Style>

完整样例代码如下：

<dxg:GridControl ItemsSource="{Binding GridData}" AutoGenerateColumns="AddNew">
    <dxg:GridControl.Columns>
        <dxg:GridColumn Header="ID" FieldName="ID"></dxg:GridColumn>
        <dxg:GridColumn Header="Text" FieldName="Text"></dxg:GridColumn>
        <dxg:GridColumn Header="Value" FieldName="Value"></dxg:GridColumn>
        <dxg:GridColumn Header="Mandatory" FieldName="Mandatory"></dxg:GridColumn>
    </dxg:GridControl.Columns>
    <dxg:GridControl.View>
        <dxg:TableView x:Name="tvTable" RowStyle="{StaticResource optimizedRowStyle}">
            <dxg:TableView.RowCellMenuCustomizations>
                <dxb:BarButtonItem Content="DB Owner"
                                   Command="{Binding Path=(dxg:DataControlBase.ActiveView).DataContext.SetTableDataHeaderCommand, RelativeSource={RelativeSource Self}}"
                           CommandParameter="{Binding ElementName=tvTable, Path=FocusedRowHandle}"
                                   dxb:BarManager.ShowGlyphsInPopupMenus="False"
                                   Style="{StaticResource barButtonItemStyle}">
                </dxb:BarButtonItem>
                <dxb:BarButtonItem Content="Table Name" IsVisible="{Binding Row.Row.Mandatory,Converter={StaticResource string2BoolConverter}}"
                                   Command="{Binding Path=(dxg:DataControlBase.ActiveView).DataContext.SetTableDataHeaderCommand, RelativeSource={RelativeSource Self}}"
                           CommandParameter="{Binding ElementName=tvTable, Path=FocusedRowHandle}">
                </dxb:BarButtonItem>
                <dxb:BarButtonItem Content="DataHeader"
                                   Command="{Binding Path=(dxg:DataControlBase.ActiveView).DataContext.SetTableDataHeaderCommand, RelativeSource={RelativeSource Self}}"
                           CommandParameter="{Binding ElementName=tvTable, Path=FocusedRowHandle}">
                </dxb:BarButtonItem>
                <dxb:BarButtonItem Content="DataBegin"
                                        Command="{Binding Path=(dxg:DataControlBase.ActiveView).DataContext.SetTableDataBeginCommand, RelativeSource={RelativeSource Self}}"
                           CommandParameter="{Binding ElementName=tvTable, Path=FocusedRowHandle}">
                </dxb:BarButtonItem>
            </dxg:TableView.RowCellMenuCustomizations>
            <dxmvvm:Interaction.Behaviors>
                <dxmvvm:EventToCommand EventName="MouseDoubleClick"
                               Command="{Binding ShowRowDetailsCommand}"
                               PassEventArgsToCommand="True">
                    <dxmvvm:EventToCommand.EventArgsConverter>
                        <dx:EventArgsToDataRowConverter/>
                    </dxmvvm:EventToCommand.EventArgsConverter>
                </dxmvvm:EventToCommand>
            </dxmvvm:Interaction.Behaviors>
        </dxg:TableView>
    </dxg:GridControl.View>
</dxg:GridControl>