如何比较两个列表框项并添加到列表框中常见的组合框 [英] how to compare two listbox items and add to anthor combo box which are common in listboxes

问题描述

我是C#的新手.我有两个`ListBoxes`

1个列表框-> lbFirstTableColumns
2列表框-> lbSecondTableColumns
组合框-> cmbJoinColumn

现在我想比较两个ListBox项并添加到我的Listboxes中常见的cmbJoinColumn中.

我尝试了以下代码，但未给出任何结果

公共无效AddJoinColumns()
{
试试
{
List< string> lstArray = new List< string>();
//将每个项目添加到lstarray
for(int index = 0; index< lbFirstTableColumns.Items.Count; index ++)
{
lstArray.Add(lbFirstTableColumns.Items [index] .ToString());
}
//比较第二个列表框中的每个列表数组项(如果有任何匹配的副本复制到组合框中)
foreach(lstArray中的字符串str)
{
MessageBox.Show(str);
如果(lbSecondTableColumns.Items.Contains(str))
{
cmbJoinColumn.Items.Add(str);
}
}
}
catch(ex ex例外)
{
MessageBox.Show(ex.Message);
}
}

I am new to C#. I have two `ListBoxes`

1 listbox --> lbFirstTableColumns
2 listbox --> lbSecondTableColumns
combo Box --> cmbJoinColumn

now I want compare two `ListBox` items and add to `cmbJoinColumn` which are common in my `Listboxes`

I have tried following code but it doesn''t give any result

public void AddJoinColumns()
{
try
{
List<string> lstArray = new List<string>();
//add each items to lstarray
for (int index = 0; index < lbFirstTableColumns.Items.Count; index++)
{
lstArray.Add(lbFirstTableColumns.Items[index].ToString());
}
//compare each listarray item in second listbox if any matching copy into combo box
foreach (string str in lstArray)
{
MessageBox.Show(str);
if (lbSecondTableColumns.Items.Contains(str))
{
cmbJoinColumn.Items.Add(str);
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}

推荐答案

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

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void bttnAdd_Click(object sender, EventArgs e)
        {
            for (int __k = 0; __k < lst_1.Items.Count; __k++)
            {
                if (lst_2.Items.Contains(lst_1.Items[__k]))
                    cbo.Items.Add(lst_1.Items[__k]);
            }
        }
    }
}

使用System.Linq

by using System.Linq

var list1 = lbFirstTableColumns.Items.Cast<string>();
var list2 = lbSecondTableColumns.Items.Cast<string>();


cbo.DataSource = list1.Intersect(list2);

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