行未在数据网格 C# 中删除

Posted 2023-04-11

【中文标题】行未在数据网格 C# 中删除

【英文标题】：Row not deleting in datagrid C#

【发布时间】：2021-05-23 19:42:32

【问题描述】：

在选择DataGridView 并按下删除按钮后，我想从我的DataGridView 中删除一行。如果我有一个 id 或 int 作为第一列输入，它确实有效。但现在我有一个nvarchar 类型一。那么我该如何解决获取input string is not in correct format 的问题。这是我的代码

// No row selected no delete....
if (dataGridView1.SelectedRows.Count == 0)
    return; // show a message here to inform

// Prepare the command text with the parameter placeholder
string sql = "DELETE FROM cabphase3 WHERE driver_name = @rowID";

// Create the connection and the command inside a using block
using (SqlConnection myConnection = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\mrdar\source\repos\HTC\HTC\Database1.mdf;Integrated Security=True"))
using (SqlCommand deleteRecord = new SqlCommand(sql, myConnection))

    myConnection.Open();

    int selectedIndex = dataGridView1.SelectedRows[0].Index;
    // gets the RowID from the first column in the grid
    int rowID = Convert.ToInt32(dataGridView1[0, selectedIndex].Value);

    // Add the parameter to the command collection
    deleteRecord.Parameters.Add("@rowID", SqlDbType.Int).Value = rowID;
    deleteRecord.ExecuteNonQuery();

    // Remove the row from the grid
    dataGridView1.Rows.RemoveAt(selectedIndex);

【问题讨论】：

评估“我有一个 nvarchar 类型”和“int rowID = Convert.ToInt32(dataGridView1[0, selectedIndex].Value);”，然后开始思考可能出了什么问题...

@Luuk 应该用什么代替 ToInt32

我希望你知道这行代码的作用：Convert.ToInt32(dataGridView1[0, selectedIndex].Value); 如果你知道这一点，那么你现在也想现在做一些不同的事情。

@HaramHoe 检查dataGridView1[0, selectedIndex].Value 的值。你会找到根本原因

【参考方案1】：

这样试试吧。

using System;
using System.Data;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1

    public partial class Form1 : Form
    
        private int rowIndex = 0;

        public Form1()
        
            InitializeComponent();
        

        private void Form1_Load(object sender, EventArgs e)
        
            DataTable dt = new DataTable();
            dt.Columns.Add("Id", typeof(int)); 
            dt.Columns.Add("Publisher Name", typeof(string));
            dt.Columns.Add("Book", typeof(string));

            for (int i = 1; i < 11; i++) 
             
                dt.Rows.Add(i, "PubName" + i, "Book"+i); 
             
            dataGridView1.DataSource = dt;
            this.dataGridView1.RowsDefaultCellStyle.BackColor = Color.Bisque;
            this.dataGridView1.AlternatingRowsDefaultCellStyle.BackColor = Color.Beige;
        



        private void dataGridView1_CellMouseUp(object sender, DataGridViewCellMouseEventArgs e)
        
            if (e.Button == MouseButtons.Right) 
            
                this.dataGridView1.Rows[e.RowIndex].Selected = true; 
                this.rowIndex = e.RowIndex;
                this.dataGridView1.CurrentCell = this.dataGridView1.Rows[e.RowIndex].Cells[1];
                this.contextMenuStrip1.Show(this.dataGridView1, e.Location);
                contextMenuStrip1.Show(Cursor.Position);
            
        

        private void contextMenuStrip1_Click(object sender, EventArgs e)
        
            if (!this.dataGridView1.Rows[this.rowIndex].IsNewRow)
            
                this.dataGridView1.Rows.RemoveAt(this.rowIndex);
            
        
    

http://csharp.net-informations.com/datagridview/deletegridview.htm