C#对ListBox控件中的数据进行的操作_Asp.net

1.添加数据：

2.删除数据：

3.清空数据：

4.选择项：

c#中对listbox控件中的数据进行的操作主要包括添加、删除、清空、选择、排序等。

1.添加数据：

// 添加一个字符串数组
listbox1.items.addrange(new string[] { "item1", "item2", "item3" });

// 或者添加单个字符串
listbox1.items.add("item4");

2.删除数据：

// 删除选定的项
listbox1.items.remove(listbox1.selecteditem);

// 或者删除第n项
listbox1.items.removeat(n);

3.清空数据：

listbox1.items.clear();

4.选择项：

// 选择第n项
listbox1.selectedindex = n;

// 或者选择包含特定文本的项
for (int i = 0; i < listbox1.items.count; i++)
{
    if (listbox1.items[i].tostring() == "item4")
    {
        listbox1.selectedindex = i;
        break;
    }
}

5.排序：

//listbox1排序);
listbox1.sorted = true;

6.获取选中的项：

int selectedindex = listbox1.selectedindex;

7.获取listbox中的所有项：

list<string> allitems = new list<string>();
foreach (string item in listbox1.items)
{
    allitems.add(item.tostring());
}

8.综合示例

// listbox控件操作
using system.diagnostics;
using system.linq;
namespace _148_2
{
    public partial class form1 : form
    {
        private static listbox? listbox1;
        private button? button1;
        private static textbox? textbox1;
        private button? button2;
        private button? button3;
        private button? button4;

        public form1()
        {
            initializecomponent();
            startposition = formstartposition.centerscreen;
            load += form1_load;
        }

        private void form1_load(object? sender, eventargs e)
        {
            // 
            // listbox1
            // 
            listbox1 = new listbox
            {
                formattingenabled = true,
                itemheight = 17,
                location = new point(12, 12),
                name = "listbox1",
                size = new size(270, 174),
                tabindex = 1
            };
            // 
            // button1
            // 
            button1 = new button
            {
                forecolor = systemcolors.activecaptiontext,
                tabindex = 2,
                text = "操作",
                usevisualstylebackcolor = true,
                location = new point(231, 221),
                name = "button1",
                size = new size(50, 23)
            };
            button1.click += button1_click;
            // 
            // textbox1
            // 
            textbox1 = new textbox
            {
                location = new point(12, 192),
                name = "textbox1",
                size = new size(270, 23),
                tabindex = 3
            };
            // 
            // button2
            // 
            button2 = new button
            {
                forecolor = systemcolors.activecaptiontext,
                tabindex = 4,
                text = "清空",
                usevisualstylebackcolor = true,
                location = new point(166, 221),
                name = "button2",
                size = new size(49, 23)
            };
            button2.click += button2_click;
            // 
            // button3
            // 
            button3 = new button
            {
                forecolor = systemcolors.activecaptiontext,
                location = new point(12, 221),
                name = "button3",
                size = new size(75, 23),
                tabindex = 5,
                text = "复制全部",
                usevisualstylebackcolor = true
            };
            button3.click += button3_click;
            // 
            // button4
            // 
            button4 = new button
            {
                forecolor = systemcolors.activecaptiontext,
                location = new point(103, 221),
                name = "button4",
                size = new size(47, 23),
                tabindex = 6,
                text = "删除",
                usevisualstylebackcolor = true
            };
            button4.click += button4_click;
            // 
            // form1
            // 
            autoscaledimensions = new sizef(7f, 17f);
            autoscalemode = autoscalemode.font;
            clientsize = new size(294, 255);
            controls.add(button4);
            controls.add(button3);
            controls.add(button2);
            controls.add(textbox1);
            controls.add(button1);
            controls.add(listbox1);
            forecolor = systemcolors.controllightlight;
            name = "form1";
            text = "listbox操作";
        }

        private void button1_click(object? sender, eventargs e)
        {
            listboxoperations();
        }

        private static void listboxoperations()
        {
            // 创建一个字符串数组
            string[] items = ["item3", "item2", "item1"];

            // 添加字符串数组到listbox
            listbox1!.items.addrange(items);

            // 添加单个字符串到listbox
            listbox1.items.add("item4");

            //listbox1排序
            listbox1.sorted = true;

            // 选择第2个项（索引从0开始）
            listbox1.selectedindex = 1;

            // 获取选中的项
            string selectedvalue = listbox1.selecteditem!.tostring()!;
            textbox1!.text = "selected value: " + selectedvalue;

            // 获取选中的项的索引
            int selectedindex = listbox1.selectedindex;
            textbox1!.text += "  selected index: " + selectedindex;
        }
        // 清空所有
        private void button2_click(object? sender, eventargs e)
        {
            listbox1!.items.clear();
        }
        // 复制并添加全部
        private void button3_click(object? sender, eventargs e)
        {
            list<string> allitems = [];
            foreach (string item in listbox1!.items)
            {
                allitems.add(item.tostring());
            }
            foreach (string item in allitems)
            {
                listbox1.items.add(item);
            }
        }
        // 删除选中
        private void button4_click(object? sender, eventargs e)
        {
            listbox1!.items.remove(listbox1.selecteditem!);
        }
    }
}