出现异常：DataGridViewComboBoxColumn值无效

Question

现有一张 物理数据表 "Question"结构如下：
Id                         int                 主键 标识列 种子：1 增量：1  Not Null;
Question               varchar(50)                                             Not Null;
Answer                 varchar(50)                                             Not Null;
Level                    int                  约束为：只能为 1或2或3        Not Null;

通过DataTable 将该物理数据源 设定到 一个 桌面程序的 DataGridView 控件 dgv(实例名)中，
为dgv 创建 四个列 分别用于显示数据源 Id,Question ,Answer,Level 
名称分别为: ColId(设为 ReadOnly=True)
                 ColQue
                 ColAns
                 以上三个列的ColumnType值为 DataGridViewTextBoxColumn
                 ColLev 的ColumnType值为 DataGridViewComboBoxColumn
如何 在 窗体 Load 的时候 将物理数据表Question显示在dgv的这四个列中，并且ColLev单元格的下拉列表值
为 1，2，3(这样使用户修改ColLev单元格的值的时候限定在 1或2或3中)
                要求是既让用户知道每条记录的当前Level是多少，又限定用户对Level的修改限定在1或2或3中，
           尝试：在ColLev.Items.AddRange(new string[] { "1","2","3" });并且ColLev.DataPropertyName="Level ";
           结果：出现异常：DataGridViewComboBoxColumn值无效
请问还有哪位能帮忙解决以上这个问题啊？不胜感激!!!!!

Answer 1

你好！
     DataGridViewComboBoxCell里的值必须要和绑定的数据里的其中的一个值相同，不相同会报这个异常的

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周雪峰

Answer 2

你好！
     你的问题我已经在另外一个帖子中做了回复，请不要重复发帖！
      多谢你的合作！

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周雪峰

Answer 3

请问针对以上案例 你有什么具体实施办法吗？

Answer 4

之前写的一个示例，包括了你描述的功能

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

namespace X.WinFormsApp
{
    public partial class X200906170939 : Form
    {
        private DataSet fEmployee;
        public DataSet Employee
        {
            get
            {
                if (fEmployee == null)
                {
                    fEmployee = new DataSet();
                    fEmployee.Tables.Add(new DataTable("Employee"));

                    fEmployee.Tables[0].Columns.Add(new DataColumn("EmployeeKey", typeof(Int32)));
                    fEmployee.Tables[0].Columns.Add(new DataColumn("DepartmentKey", typeof(Int32)));
                    fEmployee.Tables[0].Columns.Add(new DataColumn("Name", typeof(String)));
                    fEmployee.Tables[0].Columns.Add(new DataColumn("ModifyDate", typeof(DateTime)));

                    fEmployee.Tables[0].Rows.Add(new object[] { 1, 1, "John", DateTime.Now });
                    fEmployee.Tables[0].Rows.Add(new object[] { 2, 1, "Tomi", DateTime.Now });
                    fEmployee.Tables[0].Rows.Add(new object[] { 3, 2, "X.XY", DateTime.Now });
                    fEmployee.Tables[0].Rows.Add(new object[] { 4, 2, "Sam", DateTime.Now });
                    fEmployee.Tables[0].Rows.Add(new object[] { 5, 3, "Mary", DateTime.Now });
                    fEmployee.Tables[0].Rows.Add(new object[] { 6, 3, "Chirs", DateTime.Now });
                }

                return fEmployee;
            }
        }

        private DataSet fDepartment;
        public DataSet Department
        {
            get
            {
                if (fDepartment == null)
                {
                    fDepartment = new DataSet();
                    fDepartment.Tables.Add(new DataTable("Department"));

                    fDepartment.Tables[0].Columns.Add(new DataColumn("DepartmentKey", typeof(Int32)));
                    fDepartment.Tables[0].Columns.Add(new DataColumn("Name", typeof(String)));

                    fDepartment.Tables[0].Rows.Add(new object[] { 1, "A"});
                    fDepartment.Tables[0].Rows.Add(new object[] { 1, "B" });
                    fDepartment.Tables[0].Rows.Add(new object[] { 2, "C" });
                    fDepartment.Tables[0].Rows.Add(new object[] { 2, "D" });
                    fDepartment.Tables[0].Rows.Add(new object[] { 3, "E" });
                    fDepartment.Tables[0].Rows.Add(new object[] { 3, "F" });
                }

                return fDepartment;
            }
        }

        public X200906170939()
        {
            InitializeComponent();
            this.InitControls();
        }

        private void InitControls()
        {
            Button button = new Button();
            button.Dock = DockStyle.Top;
            button.Text = "保存XML";
            button.Click += new EventHandler(button_Click);
            this.Controls.Add(button);

            DataGridView fDataGridView = new DataGridView();
            fDataGridView.Dock = DockStyle.Fill;
            fDataGridView.AutoGenerateColumns = false;

            DataGridViewColumn fColumn1 = new DataGridViewColumn(new DataGridViewTextBoxCell());
            fColumn1.HeaderText = "EmployeeKey";
            fColumn1.DataPropertyName = "EmployeeKey";

            DataGridViewColumn fColumn2 = new DataGridViewColumn(new DataGridViewTextBoxCell());
            fColumn2.HeaderText = "Name";
            fColumn2.DataPropertyName = "Name";

            //DataGridViewLinkColumn fColumn = new DataGridViewLinkColumn();
            //fColumn.DataPropertyName = "你要绑定的字段名";
            //DataGridView1.Columns.Add(fColumn);
            DataGridViewComboBoxColumn fColumn3 = new DataGridViewComboBoxColumn();
            BindingSource fBindingSource = new BindingSource(this.Department, "Department");
            fColumn3.DataSource = fBindingSource;
            fColumn3.DisplayMember = "Name";
            fColumn3.ValueMember = "DepartmentKey";
            fColumn3.DataPropertyName = "DepartmentKey";

            fDataGridView.Columns.Add(fColumn1);
            fDataGridView.Columns.Add(fColumn2);
            fDataGridView.Columns.Add(fColumn3);

            fDataGridView.DataSource = this.Employee.Tables[0];
            this.Controls.Add(fDataGridView);
        }

        void button_Click(object sender, EventArgs e)
        {
            using (SaveFileDialog dialog = new SaveFileDialog())
            {
                dialog.Filter = "xml files (*.xml)|*.xml|All files (*.*)|*.*";   
                if (dialog.ShowDialog() == DialogResult.OK)
                    this.Employee.WriteXml(dialog.FileName);
            }
        }
    }
}

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知识改变命运，奋斗成就人生!

Answer 5

感谢你的回复!对我的帮助将很大。