DataGridView Cell click problem

DataGridView Cell click problem

• davros51

  The column header is a cell, and it's row index is -1. Therefore, when attempting to access a value from row of index -1 you will get an error. Also note the comment about the datagrid view settings in the sample code below.

  using System;

  using System.Collections.Generic;

  using System.ComponentModel;

  using System.Data;

  using System.Drawing;

  using System.Text;

  using System.Windows.Forms;

  namespace WindowsApplication1

  {

  public partial class Form1 : Form

  {

  public Form1()

  {

  InitializeComponent();

  }

  private void Form1_Load(object sender, EventArgs e)

  {

  // begind sample table

  DataTable dt = new DataTable("Test");

  dt.Columns.Add(new DataColumn("One"));

  dt.Columns.Add(new DataColumn("Two"));

  Int16 i =0;

  while (i<10){

  DataRow rw = dt.NewRow();

  rw["One"] = "one " + i.ToString();

  rw["Two"] = "Two " + i.ToString();

  dt.Rows.Add(rw);

  i++;

  }// end while

  // end sample table

  this.dataGridView1.DataSource = dt;

  this.dataGridView1.CellClick += this.CellClick_Handler;

  // Impact on rows selected by cell click

  // without this setting no rows selected by cell click.

  this.dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;

  }// end form load

  private void CellClick_Handler(object sender, DataGridViewCellEventArgs e)

  {

  MessageBox.Show(e.RowIndex.ToString());

  // also

  DataGridViewSelectedRowCollection rws = this.dataGridView1.SelectedRows;

  // Selected row count is zero when fullrow select is false

  if (rws != null rws.Count > 0 : false) {

  DataGridViewRow rw = rws[0];

  string ItemText1 = (string)rw.Cells["One"].Value;

  MessageBox.Show(ItemText1);

  }

  }// end cell click handler

  }//end form

  }

  Rgds,

  Martin.

  
  

• ComputerWhiz

  Hi Martin,

  Right, it is not a "bug" of any how, I just used the word error coz I have this at my end better term I guess is "user logical error" :D

  The rowEnter event works great! Magic!

  How about after loading on the datagridview the records, having the first record (row) selected

  Thanks,

  
  

• nikos_22

  Hi Martin,

  Thank you for the reply. I understand why it generates the error clearly now.

  Is there a way to know the index of highlighted row

  Thanks,

  
  

• nickst

  Hi Martin,

  Thank you for the reply, I'll try this later today and hope you wont stop helping me : )

  Thanks,

  
  

• miamikk

  The behaviour of the events is by desing and cannot be classed as an error - particularly s you are handling the selected row index of -1 in your app.

  The RowEnter event has the same signature as cell enter. The cell enter event could also be used for this, but there is no point in capturing the event and invalidating / repainting parts of your form when a user is moving within the same row.

  //.....

  this.dataGridView1.SuspendLayout();

  this.dataGridView1.DataSource = dt;

  //this.dataGridView1.CellClick += this.CellClick_Handler;

  // Impact on rows selected by cell click

  // without this setting no rows selected by cell click.

  //System.Windows.Forms.DataGridViewRowEventHandler hd = this.rowSelectedChanged;

  this.dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;

  this.dataGridView1.RowEnter += this.CellClick_Handler;

  this.dataGridView1.ResumeLayout();

  }// end form load

  private void CellClick_Handler(object sender, DataGridViewCellEventArgs e)

  {

  ////MessageBox.Show(e.RowIndex.ToString());

  ////// also

  ////DataGridViewSelectedRowCollection rws = this.dataGridView1.SelectedRows;

  ////// Selected row count is zero when fullrow select is false

  ////if (rws != null rws.Count > 0 : false) {

  //// DataGridViewRow rw = rws[0];

  //// string ItemText1 = (string)rw.Cells["One"].Value;

  //// MessageBox.Show(ItemText1);

  ////}

  // getting row with the cell

  if (e.RowIndex > -1) {

  DataGridViewRow rw = this.dataGridView1.Rows[e.RowIndex];

  string ItemText1 = (string)rw.Cells["One"].Value;

  MessageBox.Show(ItemText1);

  }

  }// end cell click handler

  Happy to be of help,

  Martin.

  
  
• DataGridView Cell click problem