MVVM 中一个Command执行多个任务

[TaoRenYan]

在WPF 的MVVM中 我只用一个Command 要执行多个任务。 比如我的一个OpenChildrenWindowCommand 当我点击“打开A窗口”时 ，显示的是A窗口 当我点击“打开B窗口”时 ，显示的是B窗口 这些都是调用同一个OpenChildrenWindowCommand 命令 只是调用的参数不同，就显示不同的窗口 以前写过的，现在竟然写不出来了。那位能帮下？

[bwangel]

在xaml中：

 <Button Content="打开A窗口"   Command="{Binding MyCommand}" CommandParameter="A"/>
 <Button Content="打开B窗口"   Command="{Binding MyCommand}" CommandParameter="B"/>

在ViewModel中大概是这样：

public ICommand OpenWindowCommand
{
get 
{
  return new RelayCommand<string>(p=> {
  if (p=="A") OpenWindowA();
else OpenWindowB
}
}
}

[TaoRenYan]

问题已经解决： 在Xaml中

<MenuItem Header="功能">
                <MenuItem Header="销售" Tag="SellUserControl"  Command="{Binding ShowChildrenWindowCommand}" 
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="采购" Tag="PurchaseUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="调拨" Tag="AllotUserControl"  Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="库存管理" Tag="StockUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="报表查询" Tag="ReportUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="用户管理" x:Name="User" Tag="UserUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding ElementName=User, Path=Tag}"/>
            </MenuItem>  

在ViewModel中

public class MainViewModel : NotificationObject
    {
        #region 数据属性
        private UserControl ctrlChildren;
        public UserControl CtrlChildren
        {
            get { return ctrlChildren; }
            set
            {
                ctrlChildren = value;
                this.NotifyPropertyChanged("CtrlChildren");
            }
        }
        #endregion

        #region 命令属性
        public ICommand ShowChildrenWindowCommand
        {
            get
            {
                return new DelegateCommand(p =>
                  {
                      this.CtrlChildren = GetChildren(p);
                  });
            }
        }
        #endregion

        #region 辅助方法
        private UserControl GetChildren(object ctrl)
        {
            Type type = App.Current.MainWindow.GetType();
            Assembly assembly = type.Assembly;
            string userControlFullName = string.Format("{0}.{1}", type.Namespace, ctrl.ToString());
            UserControl userCtrl = (UserControl)assembly.CreateInstance(userControlFullName);
            return userCtrl;
        }
        #endregion
    }

[TaoRenYan]

Xaml

<MenuItem Header="功能">
                <MenuItem Header="销售" Tag="SellUserControl"  Command="{Binding ShowChildrenWindowCommand}" 
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="采购" Tag="PurchaseUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="调拨" Tag="AllotUserControl"  Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="库存管理" Tag="StockUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="报表查询" Tag="ReportUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=Tag}"/>
                <MenuItem Header="用户管理" x:Name="User" Tag="UserUserControl" Command="{Binding ShowChildrenWindowCommand}"
                          CommandParameter="{Binding ElementName=User, Path=Tag}"/>
            </MenuItem>  

[TaoRenYan]

要加入用户控件的Grid

<Grid Grid.Column="2" >
                <UserControl Content="{Binding CtrlChildren}"/>
            </Grid>