Question

（我已经阅读了类似的帖子，但他们都对他们有所改变，使解决方案不同）

我正在移植一个使用它的WinForms应用程序：

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

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

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

在WPF中选择ComboBox中现有项目的正确方法是什么？

Answer 1

您必须使用SelectedValue。在WPF ComboBox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不会起作用。有各种方法可以向ComboBox添加项目。

您可以以声明方式或代码方式设置ItemsSource。
您可以添加ComboBoxItems等。请参阅属性窗口中的Items属性以查看可用的各种项目类型。

如果您使用带有字符串值的ItemsSource，则需要语法：cmb1.SelectedValue = "Name1"

如果您直接添加<ComboBox ...> <ComboBoxItem Content="Name1"/> </ComboBox/>等内容，则需要

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

我已经发布了一个完整的工作示例，演示了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）：

注意最后一个，你必须使用SelectedValuePath。

<强> 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>

<强> 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; }
    }
}

Answer 2

comboboxName.SelectedIndex = yourIndex;

e.g。

combobox1.SelectedIndex = 2;

在WPF ComboBox中设置所选项目

2 个答案: