datagridview ,CurrentCellChanged,AllowUserToAddRows,textbox.keydown event - vb.net

Question

my question is why add a textbox controls to datagridview ,then press keyboard to add a blank row to datagridview . but i find the cursor always jump to above row's cell,not position where i press keyboard's cell.so i get confused .
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 WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
textBox1.Visible = false;
textBox1.Width = 0;
dataGridView1.Controls.Add(textBoxenter code here1);
System.Data.DataTable dt = new DataTable();
dt.Columns.Add("Name");`enter code here`
dt.Columns.Add("Sex");
System.Data.DataRow dr;
for (int i = 0; i < 10; i++)
{
dr = dt.NewRow();
dr["Name"] = string.Format("Name{0}", i);
dr["Sex"] = string.Format("Sex{0}", i);
dt.Rows.Add(dr);
}
dataGridView1.AutoGenerateColumns = false;
dataGridView1.DataSource = dt;
}
private void dataGridView1_CurrentCellChanged(object sender, EventArgs e)
{
this.textBox1.Visible = false;
this.textBox1.Width = 0;
try
{
if (dataGridView1.Columns[dataGridView1.CurrentCell.ColumnIndex].HeaderText == "Name")
{
this.textBox1.Left = dataGridView1.GetCellDisplayRectangle(dataGridView1.CurrentCell.ColumnIndex, dataGridView1.CurrentCell.RowIndex, true).Left;`</i>`
this.textBox1.Top = dataGridView1.GetCellDisplayRectangle(dataGridView1.CurrentCell.ColumnIndex, dataGridView1.CurrentCell.RowIndex, true).Top;`</i>`
this.textBox1.Width = dataGridView1.GetCellDisplayRectangle(dataGridView1.CurrentCell.ColumnIndex, dataGridView1.CurrentCell.RowIndex, true).Width - 2;`</i>enter code here`
this.textBox1.Height = `</i>`dataGridView1.GetCellDisplayRectangle(dataGridView1.CurrentCell.ColumnIndex, dataGridView1.CurrentCell.RowIndex, true).Height - 2;
`</i>`
string str = Convert.ToString(this.dataGridView1.CurrentCell.Value); this.textBox1.Text = str;
this.textBox1.Visible = true;
}
}
catch
{
}
}
private void textBox1_Validating(object sender, CancelEventArgs e)
{
this.dataGridView1.CurrentCell.Value = this.textBox1.Text;
}
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
this.dataGridView1.AllowUserToAddRows = false;
this.dataGridView1 .AllowUserToAddRows =true ;
}
}
}

Answer 1

Alright, against my better judgement I will provide an partial answer for this.
First off, this is not VB.NET, this is C#.
Secondly, I can't find any code that actually adds a row for you or indicates that you have tried it. So I will only answer the problem you state in your comment. This since it seems a bit to hard for you to grasp and I want to be helpful.
Which is: "The question is why i press a key in textbox, the cell position would be move to the above cell".
This happens when you have selected the new row with an asterix ( * ) as row number. This is called a "Manually added row".
So now when you try to add text from your textbox you select the last row and start typing in the textbox. What happends then is that the event KeyDown is fired and it executes this command:
this.dataGridView1.AllowUserToAddRows = false;
Which, to make things simple, means "Delete the row with the asterix ( * )". So now the last row no longer exist and the DataGridView needs a new selection. The selection is then passed to the row above. So now the second last row is the last row, and it will be selected. Then you execute this command:
this.dataGridView1 .AllowUserToAddRows =true;
Which means "Create the row with the asterix ( * )", thus making the last row appear again. However, the second last row selection is not affected by adding this row again. So it remains selected. This creates the endresult that the selection jumps up to the line above.