RowStyles and Rows doesn't match in TableLayoutPanel?

Question

We are hiding controls in a TableLayoutPanel. We have been using the following code for a while for hiding a row that shouldn't be visible.

int controlRow = m_panel.GetPositionFromControl(control).Row;

m_panel.RowStyles[controlRow].SizeType = SizeType.Absolute;
m_panel.RowStyles[controlRow].Height = 0;

Now we have been adding more rows, and all of a sudden we have problems with the indexes. There are fewer RowStyles than Rows.

Is there something fishy going on, or have I misunderstood how the TableLayoutPanel works?

Answer 1

I've tried digging into the issue. The problem is that you did not add rows in a correct way. To add rows correctly, you have to ensure the value of RowCount and the number of RowStyles to be equal. You can see this right in the Form1.Designer.cs in the autogenerated code for the tableLayoutPanel. So you should do something like this:

//add a new row
tableLayoutPanel.RowCount++;
tableLayoutPanel.RowStyles.Add(newRowStyle);

The mismatching in fact does not cause a very serious problem. When the RowStyles.Count is larger than the actual RowCount, all the top RowStyles (which has count being equal to RowCount) will be used to style the rows, the rest can be seen as reserve. When the RowStyles.Count is smaller than the actual RowCount, there will be some rows not having any style and may be collapsed. Anyway using the code I posted above to add a new row will help you avoid any issue. The point is we have to ensure the number of rows and the number of RowStyles to be equal.