ArgumentOutOfRangeException - 索引超出范围。必须是非负数且小于集合的大小

Question

错误：ArgumentOutOfRangeException -- 索引超出范围。必须是非负数且小于集合的大小

场景：从 SQL Server 数据库读取数据的桌面应用程序。当我想点击按钮时，它会打开表单并从数据库中读取数据并自动将其放入数据网格视图中，但这会出现异常。我将代码放下

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

namespace BashgaheVarzeshiI2
{
    public partial class frmuser : Form
    {
        public frmuser()
        {
            InitializeComponent();
        }

        SqlConnection con = new SqlConnection("Data source=(local);initial catalog=BashgahDB; integrated security = true");
        SqlCommand cmd = new SqlCommand();

        void Display()
        {
            DataSet ds = new DataSet();
            SqlDataAdapter adp = new SqlDataAdapter();
            adp.SelectCommand = new SqlCommand();
            adp.SelectCommand.Connection = con;
            adp.SelectCommand.CommandText = "select * from Karbar";
            adp.Fill(ds, "Karbar");
            dgvUser.DataSource = ds;
            dgvUser.DataMember = "Karbar";

            dgvUser.Columns[0].HeaderText = "code";
            dgvUser.Columns[1].HeaderText = "username";
            dgvUser.Columns[2].HeaderText = "password";

            dgvUser.Columns[0].Width = 50;
        }
        private void bunifuImageButton1_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void bunifuImageButton2_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }

        private void bunifuImageButton6_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void bunifuImageButton3_Click(object sender, EventArgs e)
        {
            try
            {
                cmd.Parameters.Clear();
                cmd.Connection = con;
                cmd.CommandText = "insert into Karbar(UName,Password)values(@Uname,@Password)";
                cmd.Parameters.AddWithValue("@Uname", bunifuMaterialTextbox1.Text);
                cmd.Parameters.AddWithValue("@Password", bunifuMaterialTextbox2.Text);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
                Display();
                MessageBox.Show("Username Saved");
            }
            catch (Exception)
            {
                MessageBox.Show("Error!");
            }
        }

        private void frmuser_Load(object sender, EventArgs e)
        {
            Display();
        }

        private void bunifuImageButton4_Click(object sender, EventArgs e)
        {
            try
            {
                int x = Convert.ToInt32(dgvUser.SelectedCells[0].Value);

                cmd.Parameters.Clear();
                cmd.Connection = con;
                cmd.CommandText = "Delete From Karbar where id=@N";
                cmd.Parameters.AddWithValue("@N", x);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
                Display();
                MessageBox.Show("User Deleted!");
            }
            catch (Exception)
            {
                MessageBox.Show("Error!");
            }
        }

        private void dgvUser_SelectionChanged(object sender, EventArgs e)
        {

        }
    }
}

我该如何克服这个错误？

Answer 1

您正在尝试访问不存在且超出范围的数组元素。查看您的代码，Display 方法在 Load 上被调用，因此 Columns 索引似乎是问题所在，即您在尝试访问它们之前没有设置任何列。