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提问者：小点点

如何将WinForms组合框的SelectedItem数据绑定到文本框


我有这个UI

使用此代码

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Windows.Forms;

namespace WinFormsComboBoxDatabinding
{
    public partial class Form1 : Form
    {
        public List<Person> PersonList { get; set; }
        public Person SelectedPerson { get; set; }

        public Form1()
        {
            InitializeComponent();
            InitializePersonList();
            InitializeDataBinding();
        }

        private void InitializePersonList()
        {
            PersonList = new List<Person>
            {
                new Person { FirstName = "Bob", LastName = "Builder" },
                new Person { FirstName = "Mary", LastName = "Poppins" }
            };
        }

        private void InitializeDataBinding()
        {
            SelectedPerson = PersonList[0];

            var bindingSource = new BindingSource();
            bindingSource.DataSource = PersonList;

            comboBox.DisplayMember = "FirstName";
            //comboBox.ValueMember = "LastName";
            comboBox.DataSource = bindingSource;

            textBoxFirstName.DataBindings.Add("Text", SelectedPerson, "FirstName");
            textBoxLastName.DataBindings.Add("Text", SelectedPerson, "LastName");
        }

        private void comboBox_SelectedIndexChanged(object sender, EventArgs e)
        {
            SelectedPerson = comboBox.SelectedItem as Person;

            Debug.WriteLine($"SelectedPerson: {SelectedPerson}");
        }
    }

    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }

        public override string ToString()
        {
            return $"{FirstName} {LastName}";
        }
    }
}

关于数据绑定，我有两个问题:

>

  • 当我在组合框中选择Mary时，两个TextBox控件不会更新。这是为什么？我做错了什么？

    当我在组合框中更改文本“Mary”时，SelectedPerson对象不会从组合框中用新的名字更新，比如“Mary Changed”。如何实现更改ComboBox FirstName以更新所选人员的名字的行为？或者这是不可能的组合框？

    • 我看到，当comboBox_SelectedIndexChanged被调用时，可以设置两个TextBox控件的Text属性，但这并不是真正的数据绑定，不是吗。这将手动执行所有更新逻辑。

    如果我需要对问题补充更多细节，请告诉我。


    • 共3个答案

    匿名用户

    您不需要SelectedPerson变量。看起来你只是连接了错误的数据源。用这种方法试试看:

    textBoxFirstName.DataBindings.Add("Text", bindingSource, "FirstName");
textBoxLastName.DataBindings.Add("Text", bindingSource, "LastName");

    匿名用户

    试试这个

    private void InitializeDataBinding()
        {
            SelectedPerson = PersonList[0];

            var bindingSource = new BindingSource();
            bindingSource.DataSource = PersonList;

            comboBox.DisplayMember = "FirstName";
            comboBox.DataSource = bindingSource;

            textBoxFirstName.DataBindings.Add("Text", bindingSource, "FirstName");
            textBoxLastName.DataBindings.Add("Text", bindingSource, "LastName");
        }

private void comboBox_TextChanged(object sender, EventArgs e)
        {
            var selectedPerson = PersonList.FirstOrDefault(x => x.FirstName == comboBox.Text);
            if (selectedPerson == null) return;
            comboBox.SelectedItem = selectedPerson;
        }

    匿名用户

    您只需将ComboBox.DataSource设置为List<；Person>对象，该对象由此处的PersonList属性表示。
    向控件添加DataBinding，当ComboBox从其DataSource中选择新元素时，该控件需要更新:

    textBoxFirstName.DataBindings.Add("Text", PersonList, "FirstName");

    控件将自动更新。
    在ComboBoxSelectedIndexChanged处理程序中，可以将SelectedPerson属性值设置为当前SelectedItem，并将其强制转换为Person类。

    public List<Person> PersonList { get; set; }
public Person SelectedPerson { get; set; }

private void InitializePersonList()
{
    this.PersonList = new List<Person>
    {
        new Person { FirstName = "Bob", LastName = "Builder" },
        new Person { FirstName = "Mary", LastName = "Poppins" }
    };
}

private void InitializeDataBinding()
{
    comboBox.DisplayMember = "FirstName";
    comboBox.DataSource = this.PersonList;

    textBoxFirstName.DataBindings.Add("Text", PersonList, "FirstName");
    textBoxLastName.DataBindings.Add("Text", PersonList, "LastName");
}

private void comboBox_SelectedIndexChanged(object sender, EventArgs e)
{
    this.SelectedPerson = (Person)(sender as ComboBox).SelectedItem;
}

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