How to: Create a Custom Shapes Panel
- 3 minutes to read
The DiagramControl provides the DrawDetachedItem method that you can use to draw diagram items outside the Canvas/Shapes Panel. You can use this method to implement a custom shapes panel. This example illustrates how to create a custom toolbox based on the GridControl.
To drag an item when a user clicks a grid row, call the StartDragTool command. To draw a diagram item at a specific position, use the TranslateTransform method.
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
var toolboxItems = new ObservableCollection<DiagramShape>();
foreach (var shape in BasicShapes.Stencil.Shapes) {
toolboxItems.Add(new DiagramShape() { Shape = shape });
}
gridControl1.DataSource = toolboxItems;
}
int shapeTextOffset = 60;
Point mouseDownLocation;
GridHitInfo gridHitInfo;
private void GridView1_CustomDrawCell(object sender, DevExpress.XtraGrid.Views.Base.RowCellCustomDrawEventArgs e) {
DiagramShape shapeItem = gridView1.GetRow(e.RowHandle) as DiagramShape;
if (shapeItem == null)
return;
GraphicsState transState = e.Graphics.Save();
try {
e.Appearance.DrawString(e.Cache, e.DisplayText, new Rectangle(e.Bounds.X + shapeTextOffset, e.Bounds.Y, e.Bounds.Width - shapeTextOffset, e.Bounds.Height));
e.Cache.TranslateTransform(e.Bounds.X, e.Bounds.Y);
shapeItem.Width = 40;
shapeItem.Height = e.Bounds.Height;
diagramControl1.DrawDetachedItem(shapeItem, e.Cache);
e.Handled = true;
}
finally {
e.Graphics.Restore(transState);
}
}
private void gridControl1_MouseDown(object sender, MouseEventArgs e) {
gridHitInfo = gridView1.CalcHitInfo(e.Location);
mouseDownLocation = e.Location;
}
private void gridControl1_MouseMove(object sender, MouseEventArgs e) {
if (e.Button == MouseButtons.Left && CanStartDragDrop(e.Location)) {
StartDragDrop();
}
}
private void gridControl1_MouseLeave(object sender, EventArgs e) {
if (gridHitInfo != null)
gridHitInfo.View.ResetCursor();
gridHitInfo = null;
}
private bool CanStartDragDrop(Point location) {
return gridHitInfo.InDataRow && (Math.Abs(location.X - mouseDownLocation.X) > 2 || Math.Abs(location.Y - mouseDownLocation.Y) > 2);
}
public void StartDragDrop() {
var draggedItem = (DiagramShape)gridHitInfo.View.GetRow(gridHitInfo.RowHandle);
var tool = new FactoryItemTool("", () => "", diagram => new DiagramShape(draggedItem.Shape), new System.Windows.Size(150, 100));
diagramControl1.Commands.Execute(DiagramCommandsBase.StartDragToolCommand, tool, null);
}
}