Can't add DataRow to DataTable

[gib99]

Hello,

I'm having trouble adding a DataRow to a DataTable.

I create the DataRow like so:

DataRow row = myDataTable.NewRow();

I add things to the row, then I try to add the row back to the table:

myDataTable.Rows.Add(row);

It tells me: "This row already belongs to this table."

Ironically, if I try:

row.AcceptChanges();

it tells me: "Cannot perform this operation on a row not in the table."

so is it in the table or is it not?

myDataTable.AcceptChanges() seems to run without any exceptions, but my table is still empty.

What gives?

 

[Moregelen]

Do you have a primary key set on the table? If you do, you could have a duplicate.

I'm using this in one of my standard libraries without any problems. .NET 2.0.

[COLOR=#2B91AF]DataRow[/color] tempRow;
[COLOR=#0000FF]while[/color] (DbDataReader.Read())
{
    tempRow = tempTable.NewRow();
    [COLOR=#0000FF]for[/color] ([COLOR=#0000FF]int[/color] i = 0; i < DbDataReader.FieldCount; i++)
        tempRow[i] = DbDataReader[i];
    tempTable.Rows.Add(tempRow);
}
[COLOR=#0000FF]return[/color] tempTable;

You could always try this instead when adding the row to the table:

myDataTable.ImportRow(row);

and see if that works.

 

[gib99]

Thanks Moregelen,

I solved the problem by adding the row right after creating it.

At first, I had this:

DataRow row = myDataTable.NewRow();
row[1] = x;
row[2] = y;
row[3] = z;
myDataTable.Rows.Add(row);

But now I have this:

DataRow row = myDataTable.NewRow();
myDataTable.Rows.Add(row);
row[1] = x;
row[2] = y;
row[3] = z;

The latter seems to work.

 

[Moregelen]

Very strange.

 

[obislavu]

Solution 1:
<code>
DataRow row = dt.NewRow();
row[0] = "maria";
row[1] = "george";
dt.Rows.Add(row);
// row = dt.NewRow();
row[0] = "Helene";
row[1] = "Maxim";
dt.Rows.Add(row);
</code>
Running the above you get ""This row already belongs to this table."
Uncomment the comments and the second row is added.
Reason: In fact
<cde>
row[0] = "Helene";
row[1] = "Maxim";
</code>
modify the previous values of the same "row" object.

Solution 2:
<code>
DataRow row = dt.NewRow();
row[0] = "maria";
row[1] = "george";
dt.Rows.Add(row); // or dt.ImportRow(row);
row[0] = "Helene";
row[1] = "Maxim";
dt.ImportRow(row);

row[0] = "Christina";
row[1] = "Bill";
dt.ImportRow(row);
</code>
Explanation:
Rows.Add(dr) - add a reference of te dr DataRow object
Rows.ImportRow(dr) - add a copy of the dr DataRow object

obislavu