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I have a datagridview bound to a database-table. the dgv shows data of an item,
where the item could be everything.
when adding a new item the dgv's DataSource has 0 rows, the dgv just shows the columns (correctly).
to add data to the item, I use
to add the items id
to the new row, because the id-column is not visible in dgv.

below a two versions of the method and none works correctly.

code A :
private void Item_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
    int row = e.RowIndex;

    DataRow dr;
    if (row == SourceTable.Rows.Count) {
       dr = SourceTable.NewRow();

       dr["ID"] = this.ID;

code B :
private void Item_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
    int row = e.RowIndex;

    object  id = Item["Id",row].Value;
    if (id == null || id.ToString() == string.Empty) {
       Item["Id",row].Value = this.ID;

What I have tried:

code A : Item shows three rows, SourceTable has two rows

code B : Item shows one row, SourceTable has 0 rows

however it should be Item shows two rows, SourceTable has 1 row

what am I missing or what am I doing wrong here ?

thanks in advance
Updated 21-Feb-18 17:42pm
RickZeeland 21-Feb-18 12:55pm    
And how exactly do you define SourceTable and Item ?
j snooze 21-Feb-18 17:27pm    
are you rebinding your datagrid to the datasource after adding a row?
fheyn 22-Feb-18 4:39am    
private void DataGridLayout()
Item.DataSource = SourceTable;
Item.Columns["ID"].Visible = false;

DataTable SourceTable { get { return(Database.Datatable(ItemName); }}

Item is the dgvcontrol within the mdichild frmItem. Every form represents ONE
specific Item (i.e. a person, a car, a street...)
Database is a class that incorporates sqlserver and sqlite. (this project uses sqlite). Datatable is the table of the underlying tableadapter.
RickZeeland 22-Feb-18 5:43am    
Maybe you should set dataGridView property AllowUserToAddRows = false
Also I would move SourceTable.Rows.Add(dr); to the bottom of the if statement.
fheyn 22-Feb-18 12:07pm    
first of all thanks a lot for your response
when a set AllowUserToAddRows = false the dgv comes up empty and I can't add data at all (not the way I want to)
meanwhile I've replace the database-table with a local table that just contains the id-column (visible here).
I click the cell and get the same result : dgv shows three rows with the id in first row.

1 solution

I just can't spend the rest of this year trying to find out what's wrong so I've added
if (Item.Rows.Count > SourceTable.Rows.Count+1)

to the end of the if statement

with this it works correctly !
(actually the RemoveAt is only done when table was empty)
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