c# - 不包含 "foo"的定义

Question

我是 Visual Studio C# 的新手。当我使用 System.Windows.Forms 中的某些方法时，我不断收到以下错误

System.Windows.Forms.DataGridView does not contain a definition for 'foo' and no extension method 'foo' accepting a first argument of type System.Windows.Forms.DataGridView could be found

我的代码如下:

   private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
    {
            int i;
            i = dataGridView1.CurrentRow.Index
            textBox2.Text = dataGridView1.Item(2, i).Value
    }

正如我所说，我不止一次看到这种错误，但它发生在这里的原因是什么？谢谢

/编辑:根据要求，我添加了整个项目:

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

namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            //.Designer
        dataGridView1.AllowUserToAddRows = false;
        dataGridView1.Dock = DockStyle.None;

        PopulateDataGridView();
        }
        public void PopulateDataGridView()
        {
            dataGridView1.ColumnCount = 3;
            dataGridView1.Columns[0].Name = "ID";
            dataGridView1.Columns[1].Name = "Nombre";
            dataGridView1.Columns[2].Name = "Valor";
            dataGridView1.Columns["ID"].HeaderText = "ID";
            dataGridView1.Columns["Nombre"].HeaderText = "Nombre";
            dataGridView1.Columns["Valor"].HeaderText = "Valor";

            //DataGridView.
            dataGridView1.Rows.Add(new string[] { "1", "Nachos", "3.00" });
            dataGridView1.Rows.Add(new string[] { "2", "Pelukas", "5.70" });
            dataGridView1.Rows.Add(new string[] { "3", "Fresas", "3.50" });
            dataGridView1.Rows.Add(new string[] { "4", "Mineral", "5.50" });
            dataGridView1.Rows.Add(new string[] { "5", "Mirinda", "7.80" });
            dataGridView1.Rows.Add(new string[] { "6", "Jamaica", "2.70" });

            // Autosize.
            dataGridView1.AutoResizeColumns();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.AcceptButton = button7;
            textBox1.Focus();
        }


        [BrowsableAttribute(false)]
        public DataGridViewRowCollection Rows { get; }

       private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
                int i;
                i = dataGridView1.CurrentRow.Index
                textBox2.Text = dataGridView1.Item(2, i).Value
        }

Answer 1

我怀疑是这一行:

textBox2.Text = dataGridView1.Item(2, i).Value

我可以从 Visual Studio 帮助中看到 Item 是 DataGridView 的属性。此外，它是一个索引器，因此我希望您需要:

textBox2.Text = dataGridView1.Item[2, i].Value

即括号转换为方括号

有了括号，它认为它一定是你所指的函数，但它不是类型内置的，所以它开始寻找扩展方法。