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，我想在我的对象中获取样本数据显示在ComboBox中。代码运行，但显示的代替值（David，Helen，Joe）是文本TheProtect.UserControls.Client）

XAML：（ucDataBindingObject.xaml） p>

 < 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
高度=Auto
 mc：Ignorable =d> 
 
< Grid Width =130
 Height =240
 Margin =0> 
 
< ComboBox Width =310
 Horizo​​ntalAlignment =Left
 VerticalAlignment =Top
 ItemsSource ={Binding Path = Clients}/> ; 
< / Grid> 
< / UserControl> 
  

C＃：ucDataBindingObject.xaml.cs

 使用系统; 
 using System.Collections.Generic; 
 using System.Linq; 
 using System.Windows.Controls; 
 namespace TheProject.UserControls 
 {
 public partial class ucDataBindingObject：UserControl 
 {
 
 public List< Client>客户{get;组; } 
 
 
 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

 使用System; 
 using System.Linq; 
 
命名空间TheProject.UserControls 
 {
 public class Client 
 {
 public int ID {get;组; } 
 public string Name {get;组; } 
 
 public Client（int id，string name）
 {
 this.ID = id; 
 this.Name = name; 
} 
} 
} 
  

解决方案>

有几种方法告诉框架要显示什么

1）使用 DisplayMemberPath （这将显示命名属性）：

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

2）在ComboBox上设置 ItemTemplate 这就像＃1，除了允许你定义一个模板显示，而不只是一个属性：

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

3）添加 ToString（）到源类。如果你总是想给一个给定的类显示相同的字符串，这是有用的。 （注意，默认的 ToString（）只是类类型名称，这就是为什么你看到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。这对于将给定类类型与更复杂或风格化的模板相关联非常有用。

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

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)

<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

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

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;
        }
    }
}

解决方案

There are several ways to tell the framework what to display

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

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

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) 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) 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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