wxGrid Overview

Table of Contents

• Getting Started
• Column and Row Sizes

wxGrid and its related classes are used for displaying and editing tabular data.

wxGrid supports custom attributes for the table cells, allowing to completely customize its appearance and uses a separate grid table (wxGridTableBase-derived) class for the data management meaning that it can be used to display arbitrary amounts of data.

Getting Started

For simple applications you need only refer to the wxGrid class in your code. This example shows how you might create a grid in a frame or dialog constructor and illustrates some of the formatting functions.

// Create a wxGrid object

grid = new wxGrid( this,
                    -1,
                    wxPoint( 0, 0 ),
                    wxSize( 400, 300 ) );

// Then we call CreateGrid to set the dimensions of the grid
// (100 rows and 10 columns in this example)
grid->CreateGrid( 100, 10 );

// We can set the sizes of individual rows and columns
// in pixels
grid->SetRowSize( 0, 60 );
grid->SetColSize( 0, 120 );

// And set grid cell contents as strings
grid->SetCellValue( 0, 0, "wxGrid is good" );

// We can specify that some cells are read->only
grid->SetCellValue( 0, 3, "This is read->only" );
grid->SetReadOnly( 0, 3 );

// Colours can be specified for grid cell contents
grid->SetCellValue(3, 3, "green on grey");
grid->SetCellTextColour(3, 3, *wxGREEN);
grid->SetCellBackgroundColour(3, 3, *wxLIGHT_GREY);

// We can specify the some cells will store numeric
// values rather than strings. Here we set grid column 5
// to hold floating point values displayed with width of 6
// and precision of 2
grid->SetColFormatFloat(5, 6, 2);
grid->SetCellValue(0, 6, "3.1415");

Here is a list of classes related to wxGrid:

• wxGrid: The main grid control class itself.
• wxGridTableBase: The base class for grid data provider.
• wxGridStringTable: Simple wxGridTableBase implementation supporting only string data items and storing them all in memory (hence suitable for not too large grids only).
• wxGridCellAttr: A cell attribute, allowing to customize its appearance as well as the renderer and editor used for displaying and editing it.
• wxGridCellAttrProvider: The object responsible for storing and retrieving the cell attributes.
• wxGridColLabelWindow: The window showing the grid columns labels.
• wxGridRowLabelWindow: The window showing the grid rows labels.
• wxGridCornerLabelWindow: The window used in the upper left grid corner.
• wxGridWindow: The window representing the main part of the grid.
• wxGridCellRenderer: Base class for objects used to display a cell value.
• wxGridCellStringRenderer: Renderer showing the cell as a text string.
• wxGridCellNumberRenderer: Renderer showing the cell as an integer number.
• wxGridCellFloatRenderer: Renderer showing the cell as a floating point number.
• wxGridCellBoolRenderer: Renderer showing the cell as checked or unchecked box.
• wxGridCellEditor: Base class for objects used to edit the cell value.
• wxGridCellStringEditor: Editor for cells containing text strings.
• wxGridCellNumberEditor: Editor for cells containing integer numbers.
• wxGridCellFloatEditor: Editor for cells containing floating point numbers.
• wxGridCellBoolEditor: Editor for boolean-valued cells.
• wxGridCellChoiceEditor: Editor allowing to choose one of the predefined strings (and possibly enter new one).
• wxGridEvent: The event sent by most of wxGrid actions.
• wxGridSizeEvent: The special event sent when a grid column or row is resized.
• wxGridRangeSelectEvent: The special event sent when a range of cells is selected in the grid.
• wxGridEditorCreatedEvent: The special event sent when a cell editor is created.
• wxGridSelection: The object efficiently representing the grid selection.
• wxGridTypeRegistry: Contains information about the data types supported by the grid.

Column and Row Sizes

NB: This section will discuss the resizing of wxGrid rows only to avoid repetitions but everything in it also applies to grid columns, just replace Row in the method names with Col.

Initially all wxGrid rows have the same height, which can be modified for all of them at once using wxGrid::SetDefaultRowSize(). However, unlike simpler controls such as wxListBox or wxListCtrl, wxGrid also allows its rows to be individually resized to have their own height using wxGrid::SetRowSize() (as a special case, a row may be hidden entirely by setting its size to 0, which is done by a helper wxGrid::HideRow() method). It is also possible to resize a row to fit its contents with wxGrid::AutoSizeRow() or do it for all rows at once with wxGrid::AutoSizeRows().

Additionally, by default the user can also drag the row separator lines to resize the rows interactively. This can be forbidden completely by calling wxGrid::DisableDragRowSize() or just for the individual rows using wxGrid::DisableRowResize().

If you do allow the user to resize the grid rows, it may be a good idea to save their heights and restore it when the grid is recreated the next time (possibly during a next program execution): the functions wxGrid::GetRowSizes() and wxGrid::SetRowSizes() can help with this, you will just need to serialize wxGridSizesInfo structure returned by the former in some way and deserialize it back before calling the latter.