Searching for Records in Microsoft DataGridView
Quite often, you may need to find a particular record within the DataGridView control. This may be required, for example, to make sure that the data has been loaded into the grid correctly or to determine the position of a particular record within the grid. Currently, TestComplete does not have any special built-in routines for working with the Microsoft DataGridView control. However, DataGridView is the .NET control and can be used only within the .NET applications, which are open to TestComplete. This means that the internal properties and methods of DataGridView are also visible to TestComplete.
There are two ways to search for DataGridView records: you can search either within the grids dataset, or within the grid view itself.
Searching Within the Grids Dataset
If the DataGridView control is bound to an external dataset, you can search for the desired record within the dataset rather than within the grid itself. Searching within the grids dataset is a universal approach that is free from the grids user interface limitations. You can also use this approach if you need to obtain and process values in the grid cells rather than their displayed representation.
To obtain an object corresponding to DataGridView's dataset, you can use the
DataSource property of the grid control. Since DataGridView can be bound to several source types (for example, to a data table or to a one-dimensional array), the object returned by the
DataSource property may have a different structure in different applications, and the path to the exact object that holds the data may be different. To learn the structure of the dataset object, you can explore the object returned by the grids
DataSource property in TestCompletes Object Browser panel, or simply ask developers.
For example, if the grid is bound to the ADO.NET dataset that contains only one table, the path to the dataset table whose data is displayed in the grid is like this:
Most .NET objects that correspond to data sources have built-in method that can be used to search for a particular value within the data source. For example, if DataGridView is bound to an object that implements the
IList interface (e.g.
ArrayList), you can use the
Contains method to determine whether the data source contains the specified value, and the
IndexOf method to determine the position of the specified value within the data source.
If the grid data is specified by a
DataTable object, you can search for a desired record within the tables view, which can be referred via the tables
DefaultView property. To search for a particular record, you can use either the
FindRows method. The difference between them is that
Find returns the index of the first found row that matches the search criteria, whereas
FindRows returns the array of objects corresponding to all matching rows. The parameter of both methods is the sought-for value. To specify the column in which the search is performed, assign the column name to the views
Sort property (that is, to search within the column, it must be included in the sort order). If rows are not found using the search criteria,
Find returns -1 and
FindRows returns an empty array (with no elements).
Below is a code snippet that illustrates how to use the
Find method of the data table view to locate a particular data table row. It consists of the
FindRow routine that performs the search in the data table, and the
Main routine that specifies the search criteria and obtains the search results:
By the way, the DataView object supports complex queries, for example, searching by values in multiple columns. You can learn more about this feature in the Searching a DataView topic of MSDN.
Searching Within the Grid
Another approach that you can use to search within DataGridView, is to search within the grid itself. You can use this, for example, if the grid works in the unbound mode, or the grid is configured so that it displays data using custom formatting.
Since DataGridView does not have built-in methods for searching within the grid, you will need to implement the search algorithm yourself. A simple search algorithm implies that you iterate through the grid rows in a loop and on each iteration check whether the row meets the specified condition.
To determine the number of grid rows, you can use the grids
RowCount property. At that, if the grids
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 grids data rows is equal to the total number of rows decreased by one.
To obtain a value in a particular row and column, you can use the following properties and methods of the grid object:
.Item (ColIndex, RowIndex) property and
.get_Item (ColIndex, RowIndex) method return the grid cell specified by the zero-based row and column indices.
.Item_2 (ColName, RowIndex) property and
.get_Item_2 (ColName, RowIndex) method return the grid cell specified by the row index and column name (which is defined in the application code).
The code snippet below demonstrates how to search within the grid itself. It locates the first grid row containing John Doe in the customer column, and posts its index to the test log. If the row is not found, an error message is posted to the log instead. The example contains the following routines:
GetRowCount routine returns the number of grid rows (excluding the special Add New Row row).
FindRowByCellValue routine locates the row by the value held in the specified column. This routine returns the index of the first found row that satisfies the search criteria or -1 if the row is not found. The column is specified by its name, which is defined in the application code.
Main is the main script routine.