Diagram - Editing Restrictions

Our Diagram component allows you to restrict edit operations as needed. To prohibit a specific operation, set its corresponding method within the Editing method to false.

In this demo, the OnRequestEditOperation function implements complex logic to determine whether an operation is allowed. The reason event parameter indicates whether the event is raised by a user action or via a UI update. If a user tries to perform a prohibited action, an error message is displayed.

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Backend API

@(Html.DevExtreme().Diagram() .ID("diagram") .OnRequestEditOperation("onRequestEditOperation") .OnRequestLayoutUpdate("onRequestLayoutUpdate") .CustomShapes(cs => { cs.Add().Category("items").Type("root").BaseType("octagon").DefaultText("Development"); cs.Add().Category("items").Type("team").BaseType("ellipse").Title("Team").DefaultText("Team Name"); cs.Add().Category("items").Type("employee").BaseType("rectangle").Title("Employee").DefaultText("Employee Name"); }) .Nodes(ns => ns .DataSource(d => d .Array() .Key("ID") .Data(Model) ) .KeyExpr("ID") .TextExpr("Name") .TypeExpr("Type") .ParentKeyExpr("ParentID") .StyleExpr(new JS("itemStyleExpr")) .AutoLayout(al => al .Type(DiagramDataLayoutType.Tree) ) ) .ContextToolbox(t => t .ShapeIconsPerRow(2) .Width(100) .Shapes(new[] { "team", "employee" }) ) .Toolbox(t => t .ShapeIconsPerRow(2) .Groups(g => g .Add().Title("Items").Shapes(new[] { "team", "employee" }) ) ) .PropertiesPanel(pp => pp .Visibility(DiagramPanelVisibility.Disabled) ) ) <script type="text/javascript"> function showToast(text) { DevExpress.ui.notify({ position: { at: "top", my: "top", of: "#diagram", offset: "0 4" }, message: text, type: "warning", delayTime: 2000 }); } function onRequestLayoutUpdate(e) { for(var i = 0; i < e.changes.length; i++) { if(e.changes[i].type === 'remove') e.allowed = true; else if(e.changes[i].data.ParentID !== undefined && e.changes[i].data.ParentID !== null) e.allowed = true; } } function onRequestEditOperation(e) { var diagram = $("#diagram").dxDiagram("instance"); if(e.operation === "addShape") { if(e.args.shape.type !== "employee" && e.args.shape.type !== "team") { if(e.reason !== "checkUIElementAvailability") showToast("You can add only a 'Team' or 'Employee' shape."); e.allowed = false; } } else if(e.operation === "deleteShape") { if(e.args.shape.type === "root") { if(e.reason !== "checkUIElementAvailability") showToast("You cannot delete the 'Development' shape."); e.allowed = false; } if(e.args.shape.type === "team") { for(var i = 0; i < e.args.shape.attachedConnectorIds.length; i++) { if(diagram.getItemById(e.args.shape.attachedConnectorIds[i]).toId != e.args.shape.id) { if(e.reason !== "checkUIElementAvailability") showToast("You cannot delete a 'Team' shape that has a child shape."); e.allowed = false; break; } } } } else if(e.operation === "resizeShape") { if(e.args.newSize.width < 1 || e.args.newSize.height < 0.75) { if(e.reason !== "checkUIElementAvailability") showToast("The shape size is too small."); e.allowed = false; } } else if(e.operation === "changeConnection") { var shapeType = e.args.newShape && e.args.newShape.type; if(shapeType === "root" && e.args.connectorPosition === "end") { if(e.reason !== "checkUIElementAvailability") showToast("The 'Development' shape cannot have an incoming connection."); e.allowed = false; } if(shapeType === "employee" && e.args.connectorPosition === "start") e.allowed = false; } else if(e.operation === "changeConnectorPoints") { if(e.args.newPoints.length > 2) { if(e.reason !== "checkUIElementAvailability") showToast("You cannot add points to a connector."); e.allowed = false; } } else if(e.operation === "beforeChangeShapeText") { if(e.args.shape.type === "root") { if(e.reason !== "checkUIElementAvailability") showToast("You cannot change the 'Development' shape's text."); e.allowed = false; } } else if(e.operation === "changeShapeText") { if(e.args.text === "") { if(e.reason !== "checkUIElementAvailability") showToast("A shape text cannot be empty."); e.allowed = false; } } else if(e.operation === "beforeChangeConnectorText") { e.allowed = false; } } function itemStyleExpr(obj) { if(obj.Type === "root") return { "fill": "#ffcfc3" }; else if(obj.Type === "team") return { "fill": "#b7e3fe" }; else return { "fill": "#bbefcb" }; } </script>

using DevExtreme.NETCore.Demos.Models.SampleData; using Microsoft.AspNetCore.Mvc; namespace DevExtreme.NETCore.Demos.Controllers { public class DiagramController : Controller { public IActionResult OperationRestrictions() { return View(SampleData.OrgItemsRestrictions); } } }

#diagram { height: 600px; }