Datagridview - How to update programatically a hidden column in C# winforms.

Question

Datagridview1 contains 3 columns.
1st : ID
2nd : Name
3rd : ModifiedDate

third column is hiden

I would like to update automatically the hidden column (Modified Date) each time I modify the Second column value (Name)

Something is wrong with the next :

dataGridView1.CurrentRow.Cells(2).Value = dateTime.Now;
MyEntities.SaveChanges();

Thank you in advance.

Vulpes · Answer

Try: private void dataGridView1_CellValueChanged(object sender DataGridViewCellEventArgs e) { if(e.ColumnIndex == 1) { dataGridView1.Rows[e.RowIndex].Cells[2].Value = DateTime.Now; MyEntities.SaveChanges(); } }

Ehtesham · Answer

Consider the below working code public partial class Form1 : Form { public Form1() { InitializeComponent(); DataTable dt = new DataTable(); dt.Columns.Add(Col1 typeof(string)); dt.Columns.Add(Col2 typeof(string)); dt.Columns.Add(Col3 typeof(string)); DataRow dr = dt.NewRow(); dr[Col1] = ValRow1Col1; dr[Col2] = ValRow1Col2; dr[Col3] = ValRow1Col2; dt.Rows.Add(dr); dr = dt.NewRow(); dr[Col1] = ValRow2Col1; dr[Col2] = ValRow2Col2; dr[Col3] = ValRow2Col2; dt.Rows.Add(dr); dataGridView1.DataSource = dt; this.dataGridView1.Columns[Col3].Visible = false; } private void button1_Click(object sender EventArgs e) { this.dataGridView1.CurrentRow.Cells[Col3].Value = Changed; MessageBox.Show(this.dataGridView1.CurrentRow.Cells[Col3].Value.ToString()); } } Make sure you have selected row from datagridview

Ehtesham · Answer

Change dataGridView1.CurrentRow.Cells(2).Value = DateTime.Now to dataGridView1.CurrentRow.Cells[2].Value = DateTime.Now I assume you are getting compile time error as you are using c# not vb.net

Vulpes · Answer

I don't understand how e.RowIndex can be -1 when the CellValueChanged event fires but you definitely need e.ColumnIndex to be 1 because otherwise the third column will still be changed automatically if you change the ID column (ColumnIndex = 0) which is not what you want. So I'd use: private void dataGridView1_CellValueChanged(object sender DataGridViewCellEventArgs e) { if( e.ColumnIndex == 1 && e.RowIndex > -1 ) { dataGridView1.Rows[e.RowIndex].Cells[2].Value = DateTime.Now; MyEntities.SaveChanges(); } }

Samio · Answer

Hi vulpes When tried you proposal I got e.RowIndex = -1 Then used: if (e.RowIndex > -1) instead of (e.ColumnIndex == 1) and it worked I need your help for this please

Samio · Answer

private void dataGridView1_CellValueChanged(object sender DataGridViewCellEventArgs e) { dataGridView1.CurrentRow.Cells[3].Value = DateTime.Now; } I get error and it looks like the current row is null

Ehtesham · Answer

CellClick is the event you need to look at

Samio · Answer

Ehtesham I Think we are near of the solution. All what is needed here is just to update one datagrid cell when another just has been changed. Do you know the right event to use? Many thanks

Ehtesham · Answer

Samio I have just used datatable to bind datagridview and to give an example. You wanted to change datagridview cell values right you just have to look at button1_Click method The changes are only for gridview not for database if you want to make changes to database depending gridview you need to use dataadapter and commandbuilder for above case

Samio · Answer

I am using Entity Framework I do not know if it is possible mix it with datasets since you use in your code dataTables also it is not good practice to select the whole row each time you need to update the hidden column I think it should be better to update it once the current cell value changed.

Samio · Answer

Yes Ehtesham  that's right: dataGridView1.CurrentRow.Cells[2].Value = DateTime.Now instead of dataGridView1.CurrentRow.Cells(2).Value = DateTime.Now solved the compile error. Please have you an idea on how to change the hidden column value of the current row by code ? I mean which event of datagridview should be used to allow saving values in several rows before persisting data to the database.

Samio · Answer

dataGridView1.CurrentRow.Cells(2).Value = dateTime.Now; till now is placed in SaveButton click event. It is not its right place since we can change multiple rows in the datagridview before persisting changes to database. Could not use dt.GetChanges my dataGridView1.datasource is bindingSource1 and bindingSource1.DataSource = nw.Orders

Muralidharan Deenathayalan · Answer

Where you have placed this code ? dataGridView1.CurrentRow.Cells(2).Value = dateTime.Now; To fetch the modified records DataTable changedDatatable = dt.GetChanges(); Once the you got the modified records then you can call MyEntities.SaveChanges(); Please let me know your thoughts on this.