WPF:如何将对象绑定到 ComboBox [英] WPF: How to bind object to ComboBox

问题描述

尝试学习如何将对象绑定到各种类型的控件.在这种情况下，我希望在我的对象中获取示例数据以显示在 ComboBox 中.代码运行，但出现的不是值(David、Helen、Joe)是文本TheProtect.UserControls.Client")

Trying to learn how to bind objects to various types of controls. In this instance, I want to get sample data in my object to appear in ComboBox. The code runs but what appears instead of values (David, Helen, Joe) is text "TheProtect.UserControls.Client")

XAML: (ucDataBindingObject.xaml)

XAML: (ucDataBindingObject.xaml)

<UserControl x:Class="TheProject.UserControls.ucDataBindingObject"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             Width="Auto"
             Height="Auto"
             mc:Ignorable="d">

    <Grid Width="130"
          Height="240"
          Margin="0">

            <ComboBox Width="310"
                      HorizontalAlignment="Left"
                      VerticalAlignment="Top"
                      ItemsSource="{Binding Path=Clients}" />
    </Grid>
</UserControl>

C#:ucDataBindingObject.xaml.cs

C#: ucDataBindingObject.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Controls;
namespace TheProject.UserControls
{
    public partial class ucDataBindingObject : UserControl
    {

        public List<Client> Clients { get; set; }


        public ucDataBindingObject()
        {
            Clients = new List<Client>();
            Clients.Add(new Client(1, "David")); // sample data
            Clients.Add(new Client(2, "Helen"));
            Clients.Add(new Client(3, "Joe"));


            InitializeComponent();
            this.DataContext = this;
        }
    }

C# Client.cs

C# Client.cs

using System;
using System.Linq;

namespace TheProject.UserControls
{
    public class Client
    {
        public int ID { get; set; }
        public string Name { get; set; }

        public Client(int id, string name)
        {
            this.ID = id;
            this.Name = name;
        }
    }
}

推荐答案

有几种方法可以告诉框架要显示什么

There are several ways to tell the framework what to display

1) 使用 DisplayMemberPath 在 ComboBox 上(这将显示命名属性):

1) Use DisplayMemberPath on the ComboBox (this will display the named property):

<ComboBox ItemsSource="{Binding Path=Clients}" 
          DisplayMemberPath="Name"
/>

2) 在 ComboBox 上设置 ItemTemplate.这就像#1，除了允许您定义要显示的模板，而不仅仅是一个属性:

2) Set ItemTemplate on the ComboBox. This is like #1, except allows you to define a template to display, rather than just a property:

<ComboBox ItemsSource="{Binding Path=Clients}">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <Border BorderBrush="Green" BorderThickness="1" Padding="5">
                <TextBlock Text="{Binding Path=Name,StringFormat='Name: {0}'}" />
            </Border>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

3) 向源类添加一个 ToString() 覆盖.如果您总是想为给定的类显示相同的字符串，则很有用.(请注意，默认的 ToString() 只是类类型名称，这就是您看到TheProtect.UserControls.Client"的原因.)

3) Add a ToString() override to source class. Useful if you always want to display the same string for a given class. (Note that the default ToString() is just the class type name, which is why you see "TheProtect.UserControls.Client".)

public class Client
{
    // ...

    public override string ToString()
    {
        return string.Format("{0} ({1})", Name, ID);
    }
}

4) 添加 DataTemplate 到 XAML 资源.这对于将给定的类类型与更复杂或风格化的模板相关联非常有用.

4) Add a DataTemplate to the XAML resources. This is useful for associating a given class type with a more complex or stylized template.

<UserControl xmlns:local="clr-namespace:TheProject.UserControls">
    <UserControl.Resources>
        <DataTemplate DataType="local:Client">
            <TextBlock Text="{Binding Name}" />
        </DataTemplate>
    </UserControl.Resources>

    // ...

</UserControl>    

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