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978

answers:

1

I made a program in which I wanted to manually update the Data Grid View. -I have a Method to Refresh the DGV by clearing it and then reinserting the data. -Using the designer, I made an event handler for the DGV's CellEndEdit. Inside the Event Handler, the data gets updated & the DGV's custom refreshing method is called.

While running the program, whenever I start editing a cell & end it by selecting another one, an exception is thrown:

InvalidOperationException Operation is not valid because it results in a reentrant call to the SetCurrentCellAddressCore function.

Visual C#'s debugger marks the line that clears the data : datagridview1.Rows.Clear();

If you'd like to reproduce the problem, Make a new windows form project with visual c#, put a DataGridView object on the form, and paste the following code for the Form1.cs:

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

namespace Error___DataGridView_Updating___Cell_endedit
{
    public partial class Form1 : Form
    {
        // Objects
        DataTable dt;
        DataColumn colID;
        DataColumn colName;
        DataColumn colInfo;
        // Constructor
        public Form1()
        {
            InitializeComponent();

            Initialize_dt();
            InsertSampleData_dt();
            Initialize_dataGridView1();
        }

        // Methods
        private void Initialize_dt()
        {
            dt = new DataTable();

            // Building Columns
            // ID
            colID = new DataColumn();
            colID.ColumnName = "ID";
            colID.DataType = typeof(int);
            dt.Columns.Add(colID);

            // Name
            colName = new DataColumn();
            colName.ColumnName = "Name";
            colName.DataType = typeof(string);
            dt.Columns.Add(colName);

            //Info
            colInfo = new DataColumn();
            colInfo.ColumnName = "Info";
            colInfo.DataType = typeof(string);
            dt.Columns.Add(colInfo);
        }

        private void InsertSampleData_dt()
        {            
            DataRow row; 

            // 0
            row = dt.NewRow();
            row["ID"] = 100;
            row["Name"] = "AAAA";
            row["Info"] = "First Record";
            dt.Rows.Add(row);

            //1
            row = dt.NewRow();
            row["ID"] = 101;
            row["Name"] = "BBBB";
            row["Info"] = "Second Record";
            dt.Rows.Add(row);


            //2
            row = dt.NewRow();
            row["ID"] = 102;
            row["Name"] = "CCCC";
            row["Info"] = "Third Record";
            dt.Rows.Add(row);
        }

        private void Initialize_dataGridView1()
        {
            dataGridView1.AllowUserToAddRows = false;

            // Data Grid Definitions
            //      Row Header

            dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders;
            //      ColumnHeaders
            dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;

            // Building Columns
            #region ID
            {
                DataGridViewColumn colSGID = new DataGridViewTextBoxColumn();
                colSGID.Name = "ID";
                colSGID.HeaderText = "#";
                colSGID.ReadOnly = true;
                colSGID.Visible = false;
                colSGID.Resizable = DataGridViewTriState.False;

                dataGridView1.Columns.Add(colSGID);
            }
            #endregion

            #region Name
            {
                DataGridViewColumn colSGName = new DataGridViewTextBoxColumn();
                colSGName.Name = "Name";
                colSGName.HeaderText = "Name";

                dataGridView1.Columns.Add(colSGName);
            }
            #endregion

            #region Info
            {
                DataGridViewColumn colSGSubject = new DataGridViewTextBoxColumn();
                colSGSubject.Name = "Info";
                colSGSubject.HeaderText = "Description";

                dataGridView1.Columns.Add(colSGSubject);
            }
            #endregion

            Refresh_dataGridView1();
        }

        private void Refresh_dataGridView1()
        {
            int index;

            dataGridView1.SuspendLayout();

            dataGridView1.Rows.Clear();

            //MessageBox.Show("Cleared Data. Rebuilding...");

            foreach (DataRow row in dt.Rows)
            {
                index = dataGridView1.Rows.Add(new DataGridViewRow());

                dataGridView1.Rows[index].Cells["ID"].Value = row["ID"];
                dataGridView1.Rows[index].Cells["Name"].Value = row["Name"];
                dataGridView1.Rows[index].Cells["Info"].Value = row["Info"];

                //MessageBox.Show("row #" + index);
            }

            dataGridView1.ResumeLayout();
        }

        //Event Handlers
        private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {
            bool toUpdate = false;

            int id = (int)dataGridView1.Rows[e.RowIndex].Cells["ID"].Value;
            string columnName = dataGridView1.Columns[e.ColumnIndex].Name;
            string value = (string)dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;

            if (value == null)
            {
                value = string.Empty;
            }

            switch (columnName)
            {
                case "Name":
                    if (value == string.Empty)
                    {
                        MessageBox.Show("Name Can't Be Empty!");
                    }
                    else
                    {
                        toUpdate = true;
                    }
                    break;
                case "Info":
                    toUpdate = true;
                    break;
            }

            if (toUpdate)
            {
                foreach(DataRow row in dt.Rows)
                {
                    if ( (int)row["ID"] == id)
                    {
                        row[columnName] = value;
                    }
                }

                Refresh_dataGridView1();
            }

        }
    }
}
A: 

There's an answer by Bruce.Zhou at MSDN forums. I posted here a snippet from it. I can't post links yet so please search for his answer at the MSDN forums to view the the whole response :

... The problem can be solved by using BeginInvoke method to call the Reresh_dataGridView1 method.

  private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {
            ...................................................;
            if (toUpdate)
            {
                foreach(DataRow row in dt.Rows)
                {
                    if ( (int)row["ID"] == id)
                    {
                        row[columnName] = value;
                    }
                }

                this.BeginInvoke(new MethodInvoker(Refresh_dataGridView1));
            }
        }

...

When using this fix, whenever the new cell is selected, all the cells between it and the first cell (including) are selected. I am looking for a way to select only the new cell.