Code:
/ FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / fx / src / xsp / System / Web / UI / WebControls / HiddenField.cs / 4 / HiddenField.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Web.UI.WebControls { using System.ComponentModel; using System.Security.Permissions; using System.Collections.Specialized; ////// Inserts a hidden field into the web form. /// [ ControlValueProperty("Value"), DefaultEvent("ValueChanged"), DefaultProperty("Value"), Designer("System.Web.UI.Design.WebControls.HiddenFieldDesigner, " + AssemblyRef.SystemDesign), ParseChildren(true), PersistChildren(false), NonVisualControl(), SupportsEventValidation, ] [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)] public class HiddenField : Control, IPostBackDataHandler { private static readonly object EventValueChanged = new object(); [ DefaultValue(false), EditorBrowsable(EditorBrowsableState.Never), ] public override bool EnableTheming { get { return false; } set { throw new NotSupportedException(SR.GetString(SR.NoThemingSupport, this.GetType().Name)); } } [ DefaultValue(""), EditorBrowsable(EditorBrowsableState.Never), ] public override string SkinID { get { return String.Empty; } set { throw new NotSupportedException(SR.GetString(SR.NoThemingSupport, this.GetType().Name)); } } ////// Gets or sets the value of the hidden field. /// [ Bindable(true), WebCategory("Behavior"), DefaultValue(""), WebSysDescription(SR.HiddenField_Value) ] public virtual string Value { get { string s = (string)ViewState["Value"]; return (s != null) ? s : String.Empty; } set { ViewState["Value"] = value; } } ////// Raised when the value of the hidden field is changed on the client. /// [ WebCategory("Action"), WebSysDescription(SR.HiddenField_OnValueChanged) ] public event EventHandler ValueChanged { add { Events.AddHandler(EventValueChanged, value); } remove { Events.RemoveHandler(EventValueChanged, value); } } protected override ControlCollection CreateControlCollection() { return new EmptyControlCollection(this); } [ EditorBrowsable(EditorBrowsableState.Never), ] public override void Focus() { throw new NotSupportedException(SR.GetString(SR.NoFocusSupport, this.GetType().Name)); } protected virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection) { ValidateEvent(UniqueID); string current = Value; string postData = postCollection[postDataKey]; if (!current.Equals(postData, StringComparison.Ordinal)) { Value = postData; return true; } return false; } protected internal override void OnPreRender(EventArgs e) { base.OnPreRender(e); if (SaveValueViewState == false) { ViewState.SetItemDirty("Value", false); } } protected virtual void OnValueChanged(EventArgs e) { EventHandler handler = (EventHandler)Events[EventValueChanged]; if (handler != null) { handler(this, e); } } protected virtual void RaisePostDataChangedEvent() { OnValueChanged(EventArgs.Empty); } protected internal override void Render(HtmlTextWriter writer) { string uniqueID = UniqueID; // Make sure we are in a form tag with runat=server. if (Page != null) { Page.VerifyRenderingInServerForm(this); Page.ClientScript.RegisterForEventValidation(uniqueID); } writer.AddAttribute(HtmlTextWriterAttribute.Type, "hidden"); if (uniqueID != null) { writer.AddAttribute(HtmlTextWriterAttribute.Name, uniqueID); } if (ID != null) { writer.AddAttribute(HtmlTextWriterAttribute.Id, ClientID); } string s; s = Value; if (s.Length > 0) { writer.AddAttribute(HtmlTextWriterAttribute.Value, s); } writer.RenderBeginTag(HtmlTextWriterTag.Input); writer.RenderEndTag(); } ////// Determines whether the Value must be stored in view state, to /// optimize the size of the saved state. /// private bool SaveValueViewState { get { // Must be saved when // 1. There is a registered event handler for EventValueChanged // 2. Control is not visible, because the browser's post data will not include this control // 3. The instance is a derived instance, which might be overriding the OnValueChanged method if ((Events[EventValueChanged] != null) || (Visible == false) || (this.GetType() != typeof(HiddenField))) { return true; } return false; } } #region Implementation of IPostBackDataHandler bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection) { return LoadPostData(postDataKey, postCollection); } void IPostBackDataHandler.RaisePostDataChangedEvent() { RaisePostDataChangedEvent(); } #endregion } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu

This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- XmlAttributeAttribute.cs
- XomlCompiler.cs
- COM2PropertyDescriptor.cs
- WpfPayload.cs
- ReadOnlyHierarchicalDataSource.cs
- SyndicationDeserializer.cs
- EditModeSwitchButton.cs
- DrawingBrush.cs
- SQLSingleStorage.cs
- SaveCardRequest.cs
- DataGridViewComboBoxCell.cs
- DiscardableAttribute.cs
- BaseComponentEditor.cs
- TransformedBitmap.cs
- SelectionRange.cs
- RadioButton.cs
- MappingSource.cs
- Compilation.cs
- JapaneseLunisolarCalendar.cs
- XmlTextReaderImplHelpers.cs
- SoapIncludeAttribute.cs
- ElementProxy.cs
- BaseDataList.cs
- Run.cs
- Parser.cs
- Lasso.cs
- SqlDataSourceQueryEditorForm.cs
- TableChangeProcessor.cs
- Thickness.cs
- ProfileService.cs
- BindingCompleteEventArgs.cs
- ObjectDataSourceDesigner.cs
- DescendentsWalker.cs
- CroppedBitmap.cs
- MatrixIndependentAnimationStorage.cs
- BooleanFunctions.cs
- WebConfigurationFileMap.cs
- InputScope.cs
- TimeSpanSecondsOrInfiniteConverter.cs
- NestedContainer.cs
- XmlArrayItemAttributes.cs
- SoapFault.cs
- DescriptionAttribute.cs
- TextLineBreak.cs
- PictureBox.cs
- KeyTimeConverter.cs
- ThumbAutomationPeer.cs
- DesignerActionGlyph.cs
- OutputWindow.cs
- CodeComment.cs
- ResourceDescriptionAttribute.cs
- EntityContainerAssociationSet.cs
- CompareInfo.cs
- WsdlInspector.cs
- MetadataSource.cs
- OdbcConnectionPoolProviderInfo.cs
- DataGridViewAutoSizeColumnsModeEventArgs.cs
- AtomicFile.cs
- DynamicAttribute.cs
- ValidationHelper.cs
- SecurityHelper.cs
- Hex.cs
- CodePageEncoding.cs
- MessageDroppedTraceRecord.cs
- ThreadExceptionEvent.cs
- RunClient.cs
- InvokePattern.cs
- DependsOnAttribute.cs
- TemplateBaseAction.cs
- DocumentCollection.cs
- Timer.cs
- HtmlTableCellCollection.cs
- SqlClientFactory.cs
- CubicEase.cs
- OptionUsage.cs
- WSIdentityFaultException.cs
- ControlOperationBehavior.cs
- ForeignKeyConstraint.cs
- VirtualPath.cs
- ValueExpressions.cs
- ServiceHttpHandlerFactory.cs
- WebPartHelpVerb.cs
- MeasureItemEvent.cs
- XhtmlBasicLinkAdapter.cs
- DataSetUtil.cs
- ParameterCollection.cs
- XMLUtil.cs
- EventManager.cs
- ValidationService.cs
- VectorCollectionValueSerializer.cs
- TransactionOptions.cs
- QueryInterceptorAttribute.cs
- ParameterModifier.cs
- WSSecurityOneDotZeroReceiveSecurityHeader.cs
- ContractMethodInfo.cs
- IndexedString.cs
- TableRowCollection.cs
- PropertyMetadata.cs
- PassportIdentity.cs
- DataSourceCacheDurationConverter.cs