Editing Restrictions
The Diagram widget allows you to restrict edit operations. To prohibit an operation, set the corresponding option in the editing property to false.
In this demo, the onRequestEditOperation function implements a complex logic to determine whether an operation is allowed. The updateUI event parameter indicates whether the event is raised by user actions or UI update. If a user tries to perform a prohibited action, an error message is displayed.
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@(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")
.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 dataItem;
if(e.operation === "addShape") {
if(e.args.shape.type !== "employee" && e.args.shape.type !== "team") {
!e.updateUI && showToast("You can add only a 'Team' or 'Employee' shape.");
e.allowed = false;
}
}
else if(e.operation === "deleteShape") {
dataItem = e.args.shape && e.args.shape.dataItem;
if(dataItem && dataItem.Type === "root") {
!e.updateUI && showToast("You cannot delete the 'Development' shape.");
e.allowed = false;
}
if(dataItem && dataItem.Type === "team") {
var diagram = $("#diagram").dxDiagram("instance");
var children = diagram.getNodeDataSource().items().filter(function(item) {
return item.ParentID === dataItem.ID;
});
if(children.length > 0) {
!e.updateUI && showToast("You cannot delete a 'Team' shape that has a child shape.");
e.allowed = false;
}
}
}
else if(e.operation === "resizeShape") {
if(e.args.newSize.width < 1 || e.args.newSize.height < 0.75) {
!e.updateUI && showToast("The shape size is too small.");
e.allowed = false;
}
}
else if(e.operation === "changeConnection") {
dataItem = e.args.newShape && e.args.newShape.dataItem;
if(dataItem && dataItem.Type === "root" && e.args.connectorPosition === "end") {
!e.updateUI && showToast("The 'Development' shape cannot have an incoming connection.");
e.allowed = false;
}
if(dataItem && dataItem.Type === "team" && e.args.connectorPosition === "end") {
if(dataItem && dataItem.ParentID !== undefined && dataItem.ParentID !== null) {
!e.updateUI && showToast("A 'Team' shape can have only one incoming connection.");
e.allowed = false;
}
}
if(dataItem && dataItem.Type === "employee") {
if(e.args.connectorPosition === "start")
e.allowed = false;
if(e.args.connectorPosition === "end" && dataItem.ParentID !== undefined && dataItem.ParentID !== null) {
!e.updateUI && showToast("An 'Employee' shape can have only one incoming connection.");
e.allowed = false;
}
}
}
else if(e.operation === "changeConnectorPoints") {
if(e.args.newPoints.length > 2) {
!e.updateUI && showToast("You cannot add points to a connector.");
e.allowed = false;
}
}
else if(e.operation === "beforeChangeShapeText") {
dataItem = e.args.shape && e.args.shape.dataItem;
if(dataItem && dataItem.Type === "root") {
!e.updateUI && showToast("You cannot change the 'Development' shape's text.");
e.allowed = false;
}
}
else if(e.operation === "changeShapeText") {
if(e.args.text === "") {
!e.updateUI && showToast("A shape text cannot be empty.");
e.allowed = false;
}
}
else if(e.operation === "beforeChangeConnectorText") {
e.allowed = false;
}
}
</script>
using System.Web.Mvc;
using DevExtreme.MVC.Demos.Models.SampleData;
namespace DevExtreme.MVC.Demos.Controllers {
public class DiagramController : Controller {
public ActionResult OperationRestrictions() {
return View(SampleData.OrgItemsRestrictions);
}
}
}
#diagram {
height: 600px;
}