Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/UI/WebControls/ModelErrorMessage.cs

@@ -0,0 +1,110 @@
+//------------------------------------------------------------------------------
+// <copyright file="ModelErrorMessage.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+//------------------------------------------------------------------------------
+
+namespace System.Web.UI.WebControls {
+
+    using System.ComponentModel;
+    using System.Linq;
+    using System.Web;
+    using System.Web.ModelBinding;
+
+    /// <summary>
+    ///     Displays the first model error for a given key from the page's model state
+    /// </summary>
+    [
+    ToolboxData("<{0}:ModelErrorMessage runat=\"server\" Key=\"ModelStateKey\"></{0}:ModelErrorMessage>"),
+    DefaultProperty("Key"),
+    ParseChildren(true),
+    PersistChildren(false)
+    ]
+    public class ModelErrorMessage : Label {
+        [
+        Themeable(false),
+        WebCategory("Behavior"),
+        WebSysDescription(SR.ModelErrorMessage_ModelStateKey),
+        DefaultValue("")
+        ]
+        public string ModelStateKey {
+            get {
+                object o = ViewState["ModelStateKey"];
+                return ((o == null) ? String.Empty : (string)o);
+            }
+            set {
+                ViewState["ModelStateKey"] = value;
+            }
+        }
+
+        [
+        DefaultValue(""),
+        IDReferenceProperty,
+        WebCategory("Behavior"),
+        WebSysDescription(SR.ModelErrorMessage_AssociatedControlID),
+        Themeable(false)
+        ]
+        public override string AssociatedControlID {
+            get {
+                return base.AssociatedControlID;
+            }
+            set {
+                base.AssociatedControlID = value;
+            }
+        }
+
+        [
+        WebCategory("Behavior"),
+        Themeable(false),
+        DefaultValue(false),
+        WebSysDescription(SR.ModelErrorMessage_SetFocusOnError)
+        ]
+        public bool SetFocusOnError {
+            get {
+                object o = ViewState["SetFocusOnError"];
+                return ((o == null) ? false : (bool)o);
+            }
+            set {
+                ViewState["SetFocusOnError"] = value;
+            }
+        }
+
+        [
+        Browsable(false),
+        EditorBrowsable(EditorBrowsableState.Never),
+        PersistenceMode(PersistenceMode.Attribute)
+        ]
+        public override string Text {
+            // We don't want the Text property exposed to the developer as we're going to set it 
+            // ourselves to the value from the model state. We don't want to store it in ViewState
+            // because we want it re-evaluated on every render anyway, so storing in ViewState is
+            // just overhead.
+            get;
+            set;
+        }
+
+        protected internal override void OnPreRender(EventArgs e) {
+            base.OnPreRender(e);
+            ModelState modelState;
+            if (Page != null && Page.ModelState.TryGetValue(ModelStateKey, out modelState)) {
+                ModelError error = modelState.Errors.FirstOrDefault(modelError => !String.IsNullOrEmpty(modelError.ErrorMessage));
+                if (error != null) {
+                    Text = HttpUtility.HtmlEncode(error.ErrorMessage);
+
+                    // Render the script to set focus if there is a model error for the specified key
+                    if (SetFocusOnError) {
+                        var validateId = AssociatedControlID;
+                        if (!String.IsNullOrEmpty(validateId)) {
+                            var control = FindControl(validateId);
+                            if (control != null) {
+                                validateId = control.ClientID;
+                            }
+
+                            Page.SetValidatorInvalidControlFocus(validateId);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}