c# - 具有ComboBoxColum的WinForms数据绑定(bind)DataGridView

我正在尝试将DataGridView与业务对象一起使用。这是一个简化的场景：
-调用对象“配方”，它在配方中具有几个成分对象的BindingList
-我还有一个“数据库”，它是所有可用成分对象的BindingList

我想显示配方中所有成分的DataGridView，并允许用户从“名称”字段中的组合框中选择新的成分。

当我尝试以我认为应该的方式进行设置时，尽管可以从IngredientDB中进行选择，但不会显示配方中成分的名称，并且选择新的成分确实会更新配方中的列表。

如何获得正确显示的名称？

这是我到目前为止的内容：

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Windows.Forms;
using System.Drawing;

namespace WindowsFormsApplication1 {
    public class Ingredient {

        private String name;
        public String Name {
            get { return name; }
            set { name = value; }
        }

        private string description;
        public String Description {
            get { return description; }
            set { description = value; }
        }

        private int amount;
        public int Amount {
            get { return amount; }
            set { amount = value; }
        }

        public Ingredient(String n, String d, int a) {
            Name = n;
            Description = d;
            Amount = a;
        }

        public Ingredient() { }

    }

    public class Data {
        BindingList<Ingredient> ingredientDB = null;
        public BindingList<Ingredient> IngredientDB {
            get { return ingredientDB; }
        }

        public Data() {
            ingredientDB = new BindingList<Ingredient>();
            ingredientDB.Add(new Ingredient("rice", "a grain", 2));
            ingredientDB.Add(new Ingredient("whole wheat flour", "for baking", 1));
            ingredientDB.Add(new Ingredient("butter", "fatty", 3));
        }

    }

    public class Recipe : INotifyPropertyChanged {

        public String Name {
            get;
            set;
        }

        BindingList<Ingredient> ingredients = null;
        public BindingList<Ingredient> Ingredients {
            get { return ingredients; }
            set {
                ingredients = value;
                NotifyPropertyChanged("Ingredients");
            }
        }

        public Recipe() {
            Ingredients = new BindingList<Ingredient>();
            Ingredients.Add(new Ingredient("Water", "Wet", 2));
            Ingredients.Add(new Ingredient("Gin", "Yummy", 2));
        }


        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(String info) {
            if (PropertyChanged != null) {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }

        #endregion
    }

    public class myForm : Form {

        private DataGridView dgv;
        private BindingSource recipeBS;
        private BindingSource dataBS;
        public myForm() {
            this.Height = 200;
            this.Width = 400;
            Recipe myRecipe = new Recipe();
            Data myData = new Data();
            recipeBS = new BindingSource(myRecipe, null);
            dataBS = new BindingSource(myData, "IngredientDB");
            dgv = new DataGridView();
            dgv.Width = 400;
            dgv.DataError += new
            DataGridViewDataErrorEventHandler(DataGridView1_DataError);
            dgv.DataSource = myRecipe.Ingredients;
            // dgv.Columns.Remove("Name");
            DataGridViewComboBoxColumn comboboxColumn = new DataGridViewComboBoxColumn();
            comboboxColumn.DataPropertyName = "Name";
            comboboxColumn.HeaderText = "Name";
            comboboxColumn.DataSource = dataBS;
            comboboxColumn.DisplayMember = "Name";
            comboboxColumn.ValueMember = "Name";
            dgv.Columns.Insert(0, comboboxColumn);
            this.Controls.Add(dgv);
        }
        private void DataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs anError) { }

        [STAThreadAttribute()]
        static void Main() {
            Application.EnableVisualStyles();
            Application.Run(new myForm());
        }
    }


}

最佳答案

您的“ ingredientDB”列表中没有水或杜松子酒成分。 DataGridView的数据源设置为成分列表。加载表单后，它将根据业务对象的属性（即成分）自动创建3列（名称，说明，金额）。然后，根据您的“成分”列表（“水”和“金酒”）添加行。因此，最终结果是，DataGridView中有3列和2行，看起来像这样：

Name  | Description | Amount
Water | Wet         | 2
Gin   | Yummy       | 2

但是，您正在将DataGridViewComboBoxColumn插入第0列（即第一列），这就是问题所在。

DataGridVidwComboBoxColumn的数据源设置为dataBs BindingSource，而后者又设置为“ ingredientDB”。 “ ingredientDB”仅包含“大米”，“全麦面粉”和“黄油”的条目。当该列显示为第一行时，它将在其数据源（“ ingredientDB”）中查找名称==“ Water”的成分。此“ ingredientDB”不包含水成分，通常会引发DataGridViewDataErrorEvent。但是，您是在自己处理事件，而不对此做任何事情。因此，ComboBox中没有任何内容。 “杜松子酒”成分也会发生相同的情况。在“ ingredientDB”中找不到“金酒”成分，因此无法选择。

要解决此问题，您需要将“ Water”和“ Gin”都添加到“ ingredientDB”中：

public Data()
{
    ingredientDB = new BindingList<Ingredient>();
    ingredientDB.Add(new Ingredient("rice", "a grain", 2));
    ingredientDB.Add(new Ingredient("whole wheat flour", "for baking", 1));
    ingredientDB.Add(new Ingredient("butter", "fatty", 3));
    ingredientDB.Add(new Ingredient("Water", "Wet", 2));
    ingredientDB.Add(new Ingredient("Gin", "Yummy", 2));
}