无法设置WPF'；以编程方式显示的组合框项目文本

本文关键字：显示 方式 组合 文本 项目 编程 设置 WPF | 更新日期: 2023-09-27 18:28:18

我已经读了很多关于这个主题的书，我越来越沮丧和困惑，因为在没有MVVM的情况下，像这样简单的事情很难做到。

我正在将列表设置为：

cboLender.ItemsSource = lenders;

源列表是包含Lender对象的自定义类型列表。其属性类似于：ID和CompanyName。

然后以编程方式将其设置为：

        var selectedLender = lenders.SingleOrDefault(x => x.ID == _someId);
        cboLender.SelectedItem = selectedLender;
        cboLender.SelectedValuePath = "CompanyName";
        cboLender.SelectedValue = selectedLender.CompanyName;
        //cboLender.DisplayMemberPath = "CompanyName";

在代码中，项目被正确设置为SelectedItem，但在UI上，组合框为空。因此，看起来没有任何被选中。我也尝试了显示成员路径属性，但也不起作用。

这是一个如此简单的问题，但我一直在为我们的问题进行尝试和研究，现在我需要帮助。

无法设置WPF'；以编程方式显示的组合框项目文本

试试这个代码

 LenderList = new ObservableCollection<Lender>();
            Lender l = new Lender();
            l.CompanyName = "11212dffdd";
            l.ID = "1";
            LenderList.Add(l);
            cboLender.ItemsSource = LenderList;
            cboLender.DisplayMemberPath = "CompanyName";

            var selectedLender = LenderList.SingleOrDefault(x => x.ID == "1");
            cboLender.SelectedItem = selectedLender;
            cboLender.SelectedValuePath = "CompanyName";
            cboLender.SelectedValue = selectedLender.CompanyName;

后面的代码

namespace WpfApplication1
{
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        #region Inotify
        /// <summary>
        /// Property Change Event
        /// </summary>
        public event PropertyChangedEventHandler PropertyChanged;
        /// <summary>
        /// Property Change Method
        /// </summary>
        /// <param name="prop">Property Name</param>
        internal void RaisePropertyChanged(string prop)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(prop));
            }
        }
        #endregion
        #region Constructor
        public MainWindow()
        {
            this.DataContext = this;
            InitializeComponent();
        }
        #endregion
        #region Properties
        private ObservableCollection<Lender> lenderList;
        public ObservableCollection<Lender> LenderList
        {
            get { return lenderList; }
            set
            {
                lenderList = value;
                RaisePropertyChanged("LenderList");
            }
        }
        #endregion
        #region Events

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            LenderList = new ObservableCollection<Lender>();
            Lender l = new Lender();
            l.CompanyName = "11212dffdd";
            l.ID = "1";
            LenderList.Add(l);
            cboLender.ItemsSource = LenderList;
            cboLender.DisplayMemberPath = "CompanyName";

            var selectedLender = LenderList.SingleOrDefault(x => x.ID == "1");
            cboLender.SelectedItem = selectedLender;
            cboLender.SelectedValuePath = "CompanyName";
            cboLender.SelectedValue = selectedLender.CompanyName;
        }
        #endregion
    }
    public class Lender : INotifyPropertyChanged
    {
        #region Inotify
        /// <summary>
        /// Property Change Event
        /// </summary>
        public event PropertyChangedEventHandler PropertyChanged;
        /// <summary>
        /// Property Change Method
        /// </summary>
        /// <param name="prop">Property Name</param>
        internal void RaisePropertyChanged(string prop)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(prop));
            }
        }
        #endregion
        private string companyName;
        public string CompanyName
        {
            get { return companyName; }
            set
            {
                companyName = value;
                RaisePropertyChanged("CompanyName");
            }
        }
        private string id;
        public string ID
        {
            get { return id; }
            set
            {
                id = value;
                this.RaisePropertyChanged("ID");
            }
        }
    }
}

xaml

<Window x:Class="WpfApplication1.MainWindow"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:cef="clr-namespace:WpfApplication1"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
    Title="Window1" x:Name="testWindow" Height="500" Loaded="Window_Loaded" Width="300" >
    <Grid >
        <StackPanel x:Name="stk">
            <ComboBox x:Name="cboLender" Width="100"/>
        </StackPanel>
    </Grid>
</Window>

我认为您应该将ComboBox的SelectedIndex设置为0。默认值为-1。

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