Iterating Through Microsoft DataGridView Rows, Columns and Cells

Iterating through a grid means accessing the grid’s elements (rows, columns and cells) in a series, one by one. You may need to iterate through the Microsoft DataGridView in TestComplete if you need to locate a particular row or column, or perform the same set of operations on multiple elements.

I'll explain how to iterate through DataGridView rows, columns and cells and, as an example, save the grid data to an XML file.

Accessing DataGridView Rows, Columns and Cells

Before iterating through the grid, you need to determine the number of its rows and columns. You can do this using the grid’s RowCount and ColumnCount properties respectively. Note that if the grid’s AllowUserToAddRows property is True, the grid also has a special row that is used to add new records to the grid (it is shown as the last row and marked with the asterisk (*) in its row header). In this case, the number of the grid’s data rows is RowCount - 1.

Once you determine the number of grid rows and columns, you can iterate through them in a loop. You can access rows and columns via the grid’s Rows and Columns properties. To obtain a particular element by its index in the collection, you can use the Item (Index) property or the get_Item (Index) method. Note that the numeration of grid rows and columns is zero-based, so the index of the first grid row (column) is 0, and the index of the last row (column) equals the number of rows (columns) minus 1.

If you need to access a particular DataGridView cell, you do not need to obtain the object corresponding to the grid row and the column where the cell resides. You can quickly access the desired cell by using the grid’s Item (ColIndex, RowIndex) property or the get_Item (ColIndex, RowIndex) method. Here, the ColIndex and RowIndex parameters specify the indexes of the row and the column where the needed cell resides. Note again that numeration of grid rows and columns is zero-based. So, the grid.Item (3, 2) statement will return the cell in the fourth column and the third row.

Example

The example below demonstrates how to process DataGridView rows in a loop. It iterates through the grid rows, saves the data to an XML file and adds a link to this file to the test log. The example contains the following routines:

• Main is the main routine. It obtains the scripting object corresponding to the DataGridView control and calls SaveToXml to export the grid data to the C:GridData.xml file.
• The SaveToXml routine exports the grid data to the XML file whose full path is specified by the FileName parameter. To write data to a file, this routine uses methods of the FileSystemObject OLE object. You can find the FileSystemObject reference in the MSDN library at:
  

  http://msdn2.microsoft.com/en-gb/library/z9ty6h50.aspx.

• GetColumnCaption returns the grid column caption text.
• GetRowCount returns the number of grid rows (not counting the special Add New Row row).
• GetCellTextValue returns the text representation of the cell value or “(Nothing)” in case of the null value.
• IsNullValue is a helper routine that checks whether the specified value is a null value (that is Null, Empty or Nothing).

In these routines, the Grid parameter specifies the DataGridView control; RowIndex and ColIndex are row and column indexes respectively.