在WPF组合框中设置所选项目

本文关键字：选项 项目 设置 WPF 组合 | 更新日期: 2023-09-27 18:20:53

（我读过类似的帖子，但它们都有一个转折点，使解决方案有所不同）

我正在移植一个使用以下内容的WinForms应用程序：

myComboBox.SetSelected(myComboBox.FindString("Some Text"), true);

以编程方式选择项目。当移植到WPF时，我尝试了这个，但没有效果（项目没有被选中）：

myComboBox.SelectedItem = myComboBox.FindName("Some Text");

在WPF中，在组合框中选择现有项的正确方法是什么？

在WPF组合框中设置所选项目

您必须使用SelectedValue。在WPF组合框中，有多种方法可以实现相同的功能。因此，以编程方式选择项目的一种语法是不起作用的。有多种方法可以将项目添加到组合框中。

  1. 可以通过声明方式或在代码中设置ItemsSource
  2. 您可以添加ComboBoxItems等。请参阅属性窗口中的Items属性，查看可用的各种项目类型

如果您使用字符串值的ItemsSource，那么您需要类似以下语法：cmb1.SelectedValue = "Name1"

如果你直接添加像<ComboBox ...> <ComboBoxItem Content="Name1"/> </ComboBox/>这样的项目，那么你需要

foreach (ComboBoxItem item in cmb2.Items)
      if (item.Content.ToString() == "Name1")
      {
         cmb2.SelectedValue = item;
         break;
      }

我发布了一个完整的工作示例，演示如何在各种场景中以编程方式选择项目。示例代码（可以按原样使用）：

请注意最后一个，您必须使用SelectedValuePath。

Window1.xaml

<Window x:Class="WpfApplicationBlend.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:sys="clr-namespace:System;assembly=mscorlib"
    Title="Window1" Height="411" Width="749">
<Grid>
    <Grid Margin="30,27,491,276">
        <ComboBox x:Name="cmb1" HorizontalAlignment="Left" Margin="0,28,0,0" VerticalAlignment="Top" Width="210" Height="25" FocusVisualStyle="{DynamicResource StyleFocusDefault}">
            <ComboBox.ItemsSource>
                <CompositeCollection>
                    <sys:String>Name1</sys:String>
                    <sys:String>Name2</sys:String>
                    <sys:String>Name3</sys:String>
                    <sys:String>Name4</sys:String>
                </CompositeCollection>
            </ComboBox.ItemsSource>
        </ComboBox>
        <TextBox x:Name="tbInput1" HorizontalAlignment="Left" Height="23" Margin="10,0,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button Content="Button" HorizontalAlignment="Left" Margin="135,1,0,0" VerticalAlignment="Top" Width="75" Click="Button1_Click"/>
    </Grid>
    <Grid Margin="405,27,111,276">
        <ComboBox x:Name="cmb2" HorizontalAlignment="Left" Margin="0,28,0,0" VerticalAlignment="Top" Width="210" Height="25" FocusVisualStyle="{DynamicResource StyleFocusDefault}">
            <ComboBoxItem Content="Name1"/>
            <ComboBoxItem Content="Name2"/>
            <ComboBoxItem Content="Name3"/>
        </ComboBox>
        <TextBox x:Name="tbInput2" HorizontalAlignment="Left" Height="23" Margin="10,0,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button Content="Button" HorizontalAlignment="Left" Margin="135,1,0,0" VerticalAlignment="Top" Width="75" Click="Button2_Click"/>
    </Grid>
    <Grid Margin="30,207,491,96">
        <ComboBox x:Name="cmb3" HorizontalAlignment="Left" Margin="0,28,0,0" VerticalAlignment="Top" Width="210" Height="25" FocusVisualStyle="{DynamicResource StyleFocusDefault}">
            <ComboBox.ItemsSource>
                <CompositeCollection>
                    <sys:String>Name1</sys:String>
                    <sys:Boolean>True</sys:Boolean>
                    <sys:Int32>123</sys:Int32>
                </CompositeCollection>
            </ComboBox.ItemsSource>
        </ComboBox>
        <TextBox x:Name="tbInput3" HorizontalAlignment="Left" Height="23" Margin="10,0,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button Content="Button" HorizontalAlignment="Left" Margin="135,1,0,0" VerticalAlignment="Top" Width="75" Click="Button3_Click"/>
    </Grid>
    <Grid Margin="405,207,116,96">
        <ComboBox x:Name="cmb4" HorizontalAlignment="Left" Margin="0,28,0,0" VerticalAlignment="Top" Width="210" Height="25" SelectedValuePath="Name" DisplayMemberPath="Name">
        </ComboBox>
        <TextBox x:Name="tbInput4" HorizontalAlignment="Left" Height="23" Margin="10,0,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button Content="Button" HorizontalAlignment="Left" Margin="135,1,0,0" VerticalAlignment="Top" Width="75" Click="Button4_Click"/>
    </Grid>
</Grid>
  </Window>

Window1.xaml.cs

using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Collections;
namespace WpfApplicationBlend
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            List<Employee> employees = new List<Employee>()
            {
                new Employee(){Name="Name1", Age=100},
                new Employee(){Name="Name2", Age=101},
            };
            cmb4.ItemsSource = employees;
        }
        private void Button1_Click(object sender, RoutedEventArgs e)
        {
            cmb1.SelectedValue = tbInput1.Text;
        }
        private void Button2_Click(object sender, RoutedEventArgs e)
        {
            foreach (ComboBoxItem item in cmb2.Items)
                if (item.Content.ToString() == tbInput2.Text)
                {
                    cmb2.SelectedValue = item;
                    break;
                }
        }
        private void Button3_Click(object sender, RoutedEventArgs e)
        {
            foreach (object item in cmb3.Items)
                if (item.ToString() == tbInput3.Text)
                {
                    cmb3.SelectedValue = item;
                    break;
                }
        }
        private void Button4_Click(object sender, RoutedEventArgs e)
        {
            cmb4.SelectedValue = tbInput4.Text;
        }
    }
    public class Employee
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }
}

comboboxName.SelectedIndex = yourIndex;

例如

combobox1.SelectedIndex = 2;
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