DataGridView's UserDeletingRow method is called 3 times by itself

Question

I created new windows form application with DataGridView. This is the only form it has. The MessageBox in DataGridView1_UserDeletingRow method is called 3 times. I rly need to understand why is that. The obvious problem is DataSource, because adding rows manually to dataGridView, method is not unnecessarily called 3 times.

I also found out that if I put this line of code

dataGridView1.RowsRemoved += new DataGridViewRowsRemovedEventHandler(DataGridView1_UserDeletingRow);

after

dataGridView1.DataSource = dt;

everything works fine and method DataGridView1_UserDeletingRow is not called.

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

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void DataGridView1_UserDeletingRow(object sender, DataGridViewRowsRemovedEventArgs e)
        {
            MessageBox.Show(sender.ToString());
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            dataGridView1.RowsRemoved += new DataGridViewRowsRemovedEventHandler(DataGridView1_UserDeletingRow);

            var dt = new DataTable("myTableName");
            dt.Columns.Add("myColumnName");
            dt.Rows.Add(new object[] { 123 });

            dataGridView1.DataSource = dt;
        }
    }
}

Can anyone please explain what exactly is happening?

Answer 1

Hey I just had the same problem and this is how I fixed it:

protected override void OnUserDeletedRow(DataGridViewRowEventArgs e)
{
    base.OnUserDeletedRow(e);

    //You're code here
}

I used override on the DataGridView function OnUserDeletedRow, called the base function and added the code I wanted to trigger.

This function only triggered once and solved my problem, you can also override other function like this as an alternative to listening to an event.

Good luck.