Overview
TRows is a grid band class that paints multiple rows of column cells. It includes support for hierarchical “rows-inside-rows” through the Children property, enabling master-detail row structures.
Key Properties
Default height for all rows in pixels. Individual row heights can be overridden using the Heights property.Grid.Rows.Height.Value := 25; // 25 pixels per row
Individual height for a specific row. Allows different rows to have different heights.Grid.Rows.Heights[0] := 30; // First row 30 pixels
Grid.Rows.Heights[1] := 20; // Second row 20 pixels
Vertical spacing between rows in pixels.Grid.Rows.Spacing.Value := 2; // 2 pixels between rows
Background formatting for all rows. Defines the default background color, gradient, and other visual properties.Grid.Rows.Back.Brush.Color := clWhite;
Formatting properties for odd-numbered rows. Enables alternating row colors for better readability.Grid.Rows.Alternate.Visible := True;
Grid.Rows.Alternate.Brush.Color := clSilver;
Stroke properties for horizontal lines between rows.Grid.Rows.RowLines.Visible := True;
Grid.Rows.RowLines.Color := clGray;
Grid.Rows.RowLines.Width := 1;
Selection and formatting properties for the cell under the mouse cursor.Grid.Rows.Hover.Visible := True;
Grid.Rows.Hover.Format.Brush.Color := clYellow;
The data source for the rows. Must be assigned to display data in the grid.Grid.Rows.Data := MyVirtualData;
Collection of optional sub-rows for each row. Enables hierarchical row structures.var
SubRow: TGridBand;
begin
SubRow := Grid.Rows.Children.Add;
// Configure sub-row
end;
Collection of additional bands that can be displayed for each row.
Internal property containing an array of all visible columns. Used for rendering.
Calculated vertical spacing value used internally for rendering.
Key Methods
Returns the height of the specified row, taking into account custom heights or the default height.var
H: Single;
begin
H := Grid.Rows.HeightOf(5); // Height of row 5
end;
Returns the Y coordinate of the top edge of the specified row.var
Y: Single;
begin
Y := Grid.Rows.TopOf(10); // Top position of row 10
end;
Returns the Y coordinate of the bottom edge of the specified row.var
Y: Single;
begin
Y := Grid.Rows.BottomOf(10); // Bottom position of row 10
end;
RowAt(Y, AvailableHeight)
Returns the row index at the specified Y coordinate, or -1 if no row is found.var
RowIndex: Integer;
begin
RowIndex := Grid.Rows.RowAt(100, Grid.Height);
end;
Returns the index of the first visible row, optionally offset by the specified amount.var
FirstRow: Integer;
begin
FirstRow := Grid.Rows.FirstVisible(Grid.Rows.Scroll.Y);
end;
Calculates the automatic height for the specified row based on cell content.var
H: Single;
begin
H := Grid.Rows.AutoHeight(5);
Grid.Rows.Heights[5] := H;
end;
Returns true if all rows have the same height.
Returns true if there are no rows to display (data is empty).
Returns the Y coordinate of the bottom of the last row.
Calculates and sets the default row height based on font size and cell formatting.Grid.Rows.CalcDefaultHeight;
Clears all row-specific data and resets to initial state. Swaps two rows at the specified indices.Grid.Rows.Swap(0, 5); // Swap first and sixth rows
Usage Examples
Basic Row Configuration
begin
// Set default row height
Grid.Rows.Height.Value := 30;
// Configure row spacing
Grid.Rows.Spacing.Value := 1;
// Enable row lines
Grid.Rows.RowLines.Visible := True;
Grid.Rows.RowLines.Color := clSilver;
end;
Alternating Row Colors
begin
// Set default row background
Grid.Rows.Back.Brush.Color := clWhite;
// Configure alternate row formatting
Grid.Rows.Alternate.Visible := True;
Grid.Rows.Alternate.Brush.Color := RGB(240, 240, 240);
end;
Custom Row Heights
var
i: Integer;
begin
// Set individual row heights
for i := 0 to Grid.Rows.Data.Count - 1 do
begin
if i mod 3 = 0 then
Grid.Rows.Heights[i] := 40 // Every third row is taller
else
Grid.Rows.Heights[i] := 25;
end;
end;
Auto-Height Rows
var
i: Integer;
H: Single;
begin
// Calculate automatic height for each row
for i := 0 to Grid.Rows.Data.Count - 1 do
begin
H := Grid.Rows.AutoHeight(i);
Grid.Rows.Heights[i] := H;
end;
end;
Row Hover Effect
begin
// Enable hover highlighting
Grid.Rows.Hover.Visible := True;
Grid.Rows.Hover.Format.Brush.Color := clYellow;
Grid.Rows.Hover.Format.Transparency := 128; // Semi-transparent
end;
Finding Rows
var
RowIndex: Integer;
Y: Single;
begin
// Find row at mouse position
RowIndex := Grid.Rows.RowAt(Mouse.Y, Grid.Height);
if RowIndex >= 0 then
begin
// Get row position
Y := Grid.Rows.TopOf(RowIndex);
ShowMessage(Format('Row %d at Y=%g', [RowIndex, Y]));
end;
end;
Hierarchical Rows
var
DetailBand: TGridBand;
begin
// Add sub-rows (detail rows)
DetailBand := Grid.Rows.Children.Add;
DetailBand.Height.Value := 20;
// Check if children are visible for a specific row
if Grid.Rows.IsChildrenVisible(nil, 5) then
ShowMessage('Row 5 has visible children');
end;
TRows class includes scroll support:
begin
// Access scroll position
ShowMessage('Vertical scroll: ' + FloatToStr(Grid.Rows.Scroll.Y));
// Get first visible row after scrolling
var FirstRow := Grid.Rows.FirstVisible(Grid.Rows.Scroll.Y);
end;
