DataTemplateSelector选择判断对象问题

Question

xaml代码

<Window x:Class="test.PowerSupplySystem"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="PowerSupplySystem" Height="314" Width="476" 
        xmlns:dts="clr-namespace:test">
    <Window.Resources>
        <DataTemplate x:Key="SwitchDataTemplate">
          <StackPanel Margin="3">
                <TextBox Text="{Binding Mswitch}"/>
                <Image Source="/IMAGE/断路器.bmp"/>
                </StackPanel>
        </DataTemplate>

        <DataTemplate x:Key="cableDataTemplate">
            <StackPanel Margin="3">
                <TextBox Text="{Binding Mswitch}"/>
                <Image Source="/IMAGE/电缆.bmp"/>
            </StackPanel>
        </DataTemplate>

        
         

    </Window.Resources>

    <Grid>
        <DataGrid Name="system" Loaded="Window_Loaded" AutoGenerateColumns="False" >
            <DataGrid.Columns >
                <DataGridTemplateColumn Width="150" Header="开关"   />
                <DataGridTextColumn Width="300" Header="电缆"  Binding="{Binding Mcable}" />
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
    </Window>

C#代码

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using BLL;

namespace test
{
    /// <summary>
    /// PowerSupplySystem.xaml 的交互逻辑
    /// </summary>
    public partial class PowerSupplySystem : Window
    {
        public PowerSupplySystem()
        {
            InitializeComponent();
        }

       
        //启动时加载
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            system.ItemsSource = PowerSupplySystemBll.GetAll();

        }

    }

    public class TaskListDataTemplateSelector : DataTemplateSelector
    {
        public override DataTemplate
            SelectTemplate(object item, DependencyObject container)
        {
            FrameworkElement element = container as FrameworkElement;

            if (element != null && item != null && item is System)
            {
                Task taskitem = item as Task;

                if (System.内容!=null)
                    return
                        element.FindResource("SwitchDataTemplate") as DataTemplate;
                else
                    return
                        element.FindResource("cableDataTemplate") as DataTemplate;
            }

            return null;
        }
    }

这个项目我想采用模板控制器，通过判断datagrid里面Columns是否有内容，作为依据选择模板。

现在想问的是怎么才能在C#里面调用到这个datagrid的内容？

Answer 1

具体想实现的功能就是，根据单元格里面的数据选择模板，当有数据时，加载一个模板，没有数据时加载另外一个模板

Answer 2

Hi  yzjjhk,

>>这个项目我想采用模板控制器，通过判断datagrid里面Columns是否有内容，作为依据选择模板。

请参考下面的例子来实现。

XAML:

 <Window.Resources>
        <DataTemplate x:Key="SwitchDataTemplate">
            <StackPanel Margin="3">
                <TextBox Text="{Binding FirstName}"/>
                <Image Source="\images\bac.JPG"/>
            </StackPanel>
        </DataTemplate>

        <DataTemplate x:Key="cableDataTemplate">
            <StackPanel Margin="3">
                <TextBox Text="{Binding FirstName}"/>
              
                <Image Source="\images\Gakuse.ico"/>
            </StackPanel>
        </DataTemplate>
    </Window.Resources>

    <Grid>
        <DataGrid ItemsSource="{Binding}" Name="system" Loaded="Window_Loaded" AutoGenerateColumns="False" >
            <DataGrid.Columns >
                <DataGridTemplateColumn  Width="150" Header="开关">
                    <DataGridTemplateColumn.CellTemplateSelector>
                        <local:TestStudentTemplateSelector 
                            SwitchDataTemplate="{StaticResource SwitchDataTemplate}"
                            cableDataTemplate="{StaticResource cableDataTemplate}"/>
                    </DataGridTemplateColumn.CellTemplateSelector>
                </DataGridTemplateColumn>
                <DataGridTextColumn Width="300" Header="电缆"  Binding="{Binding FirstName}" />
            </DataGrid.Columns>
        </DataGrid>
    </Grid>

XAML.CS:

public partial class DataTemplateSelectordEMO2 : Window
    {

        ObservableCollection<TestStudent> teststudents = new ObservableCollection<TestStudent>();


        public DataTemplateSelectordEMO2()
        {
            InitializeComponent();

            teststudents.Add(new TestStudent(10, "Bob"));
            teststudents.Add(new TestStudent(25, "James"));
            teststudents.Add(new TestStudent(15, "Joe"));
            teststudents.Add(new TestStudent(12, "Dona"));
            teststudents.Add(new TestStudent(18, "Peter"));
            DataContext = teststudents;
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {




        }
    }


    public class TestStudentTemplateSelector : DataTemplateSelector
    {
        public DataTemplate SwitchDataTemplate
        { get; set; }

        public DataTemplate cableDataTemplate

        { get; set; }

        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            TestStudent student = item as TestStudent;
            if (student != null)
            {
                if (student.ID >= 15)
                    return SwitchDataTemplate;
                else
                    return cableDataTemplate;
            }
            else
                return base.SelectTemplate(item, container);
        }

    }

    public class TestStudent
    {
        public TestStudent(int id, String firstName )
        {
            ID = id;
            FirstName = firstName;
        }

        public int ID
        { get; set; }

        public String FirstName
        { get; set; }

    }

Best Regards,

Yohann Lu

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