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每个循环的组合框

[英]combobox with for each loop

Hi I am a student do anybody know after populating the combobox with the database values. 嗨,我是一个学生,用数据库值填充组合框后,有人知道吗。 How to display the same value in the text box. 如何在文本框中显示相同的值。 When I select a name in the combobox the same name should be displayed in the text box I am using seleted item. 当我在组合框中选择一个名称时,应在我正在使用分隔项目的文本框中显示相同的名称。 Here is the code. 这是代码。

I am getting the error the following error using the foreach loop 我使用foreach循环收到以下错误

foreach statement cannot operate on variables of type 'object' because 'object' does not contain a public definition for 'GetEnumerator' foreach语句无法对类型为“对象”的变量进行操作,因为“对象”不包含“ GetEnumerator”的公共定义

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;
using System.Data.OleDb;

namespace DBExample
{
    public partial class Form1 : Form
    {
        private OleDbConnection dbConn; // Connectionn object
        private OleDbCommand dbCmd;     // Command object
        private OleDbDataReader dbReader;// Data Reader object
        private Member aMember;
        private string sConnection;
        // private TextBox tb1;
        // private TextBox tb2;

        private string sql;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            try
            {
                // Construct an object of the OleDbConnection 
                // class to store the connection string 
                // representing the type of data provider 
                // (database) and the source (actual db)
                sConnection =
                    "Provider=Microsoft.Jet.OLEDB.4.0;" +
                    "Data Source=c:member.mdb";
                dbConn = new OleDbConnection(sConnection);
                dbConn.Open();

                // Construct an object of the OleDbCommand 
                // class to hold the SQL query. Tie the  
                // OleDbCommand object to the OleDbConnection
                // object
                sql = "Select * From memberTable Order " +
                      "By LastName , FirstName ";
                dbCmd = new OleDbCommand();
                dbCmd.CommandText = sql;
                dbCmd.Connection = dbConn;

                // Create a dbReader object 
                dbReader = dbCmd.ExecuteReader();

                while (dbReader.Read())
                {
                    aMember = new Member
                            (dbReader["FirstName"].ToString(),
                             dbReader["LastName"].ToString(),
                             dbReader["StudentId"].ToString(),
                             dbReader["PhoneNumber"].ToString());

                    // tb1.Text = dbReader["FirstName"].ToString();
                    // tb2.Text = dbReader["LastName"].ToString();

                    // tb1.Text = aMember.X().ToString();


                    //tb2.Text = aMember.Y(aMember.ID).ToString();  

                    this.comboBox1.Items.Add(aMember.FirstName.ToString());

                    // this.listBox1.Items.Add(aMember.ToString());
                    // MessageBox.Show(aMember.ToString());
                    // Console.WriteLine(aMember.ToString());
                }
                dbReader.Close();
                dbConn.Close();
            }

            catch (System.Exception exc)
            {
                MessageBox.Show("show" + exc);
            }
        }
        private void DbGUI_Load(object sender, EventArgs e)
        {

        }


        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

            this.textBox1.Text = comboBox1.SelectedItem.ToString();

            textBox2.Text = string.Empty;
            foreach (var item in comboBox1.SelectedItem)
                textBox2.Text += item.ToString();
        }


        private void textBox2_TextChanged(object sender, EventArgs e)
        {

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }






}

You just need to change the foreach loop to: 您只需要将foreach循环更改为:

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

            this.textBox1.Text = comboBox1.SelectedItem.ToString();

            textBox2.Text = string.Empty;
            foreach (var item in comboBox1.Items)
                textBox2.Text += item.ToString();
        }

the above foreach(var item in comboBox1.Items) item.ToString() just returns the system type 上面的foreach(comboBox1.Items中的var项)item.ToString()仅返回系统类型

the below example worked for me to find the one I needed 下面的示例为我找到了我需要的那个

foreach(DataRowView item in cmbUser.Items)
{
    if(item.Row[0].ToString() == "something")\\gets value displayed
    {
        //do something
    }
}

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