DataSourceControl.RaiseDataSourceChangedEvent メソッド
アセンブリ: System.Web (system.web.dll 内)

Dim e As EventArgs Me.RaiseDataSourceChangedEvent(e)

RaiseDataSourceChangedEvent メソッドは、基になるデータ ソースまたはメモリにキャッシュされたデータが変更されたため、コントロールをバインドし直し、必要な作業を実行する必要があることをデータ バインド コントロールに通知します。通常、RaiseDataSourceChangedEvent メソッドは、データ ソース コントロールのプロパティが変更された場合、またはパラメータ値が変更された場合に呼び出されます。
イベントが発生すると、デリゲートを使用してイベント ハンドラが呼び出されます。詳細については、「イベントの発生」を参照してください。
継承時の注意 派生クラスで RaiseDataSourceChangedEvent をオーバーライドする場合は、登録されているデリゲートがイベントを受け取ることができるように、基本クラスの RaiseDataSourceChangedEvent メソッドを呼び出してください。
バインド コントロールに影響を与える可能性のある方法でデータ ソースまたはその基になるデータが変更された場合に、RaiseDataSourceChangedEvent メソッドを呼び出す方法を次のコード例に示します。この例では、FileName プロパティが変更されるたびに RaiseDataSourceChangedEvent を呼び出して、DataSourceControl クラスを拡張するファイル ベースのデータ ソース コントロールから DataSourceChanged イベントを発生させます。
Imports System Imports System.Collections Imports System.Data Imports System.IO Imports System.Security.Permissions Imports System.Web Imports System.Web.UI Imports System.Web.UI.WebControls Namespace Samples.AspNet.VB.Controls ' The CsvDataSource is a data source control that retrieves its ' data from a comma-separated value file. <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _ Public Class CsvDataSource Inherits DataSourceControl Public Sub New() End Sub 'New ' The comma-separated value file to retrieve data from. Public Property FileName() As String Get Return CType(Me.GetView([String].Empty), CsvDataSourceView).SourceFile End Get Set ' Only set if it is different. If CType(Me.GetView([String].Empty), CsvDataSourceView).SourceFile <> value Then CType(Me.GetView([String].Empty), CsvDataSourceView).SourceFile = value RaiseDataSourceChangedEvent(EventArgs.Empty) End If End Set End Property ' Do not add the column names as a data row. Infer columns if the CSV file does ' not include column names. Public Property IncludesColumnNames() As Boolean Get Return CType(Me.GetView([String].Empty), CsvDataSourceView).IncludesColumnNames End Get Set ' Only set if it is different. If CType(Me.GetView([String].Empty), CsvDataSourceView).IncludesColumnNames <> value Then CType(Me.GetView([String].Empty), CsvDataSourceView).IncludesColumnNames = value RaiseDataSourceChangedEvent(EventArgs.Empty) End If End Set End Property ' Return a strongly typed view for the current data source control. Private view As CsvDataSourceView = Nothing Protected Overrides Function GetView(viewName As String) As DataSourceView If view Is Nothing Then view = New CsvDataSourceView(Me, String.Empty) End If Return view End Function 'GetView ' The ListSourceHelper class calls GetList, which ' calls the DataSourceControl.GetViewNames method. ' Override the original implementation to return ' a collection of one element, the default view name. Protected Overrides Function GetViewNames() As ICollection Dim al As New ArrayList(1) al.Add(CsvDataSourceView.DefaultViewName) Return CType(al, ICollection) End Function 'GetViewNames End Class 'CsvDataSource ' The CsvDataSourceView class encapsulates the ' capabilities of the CsvDataSource data source control. Public Class CsvDataSourceView Inherits DataSourceView Public Sub New(owner As IDataSource, name As String) MyBase.New(owner, DefaultViewName) End Sub 'New ' The data source view is named. However, the CsvDataSource ' only supports one view, so the name is ignored, and the ' default name used instead. Public Shared DefaultViewName As String = "CommaSeparatedView" ' The location of the .csv file. Private aSourceFile As String = [String].Empty Friend Property SourceFile() As String Get Return aSourceFile End Get Set ' Use MapPath when the SourceFile is set, so that files local to the ' current directory can be easily used. Dim mappedFileName As String mappedFileName = HttpContext.Current.Server.MapPath(value) aSourceFile = mappedFileName End Set End Property ' Do not add the column names as a data row. Infer columns if the CSV file does ' not include column names. Private columns As Boolean = False Friend Property IncludesColumnNames() As Boolean Get Return columns End Get Set columns = value End Set End Property ' Get data from the underlying data source. ' Build and return a DataView, regardless of mode. Protected Overrides Function ExecuteSelect(selectArgs As DataSourceSelectArguments) _ As System.Collections.IEnumerable Dim dataList As IEnumerable = Nothing ' Open the .csv file. If File.Exists(Me.SourceFile) Then Dim data As New DataTable() ' Open the file to read from. Dim sr As StreamReader = File.OpenText(Me.SourceFile) Try ' Parse the line Dim dataValues() As String Dim col As DataColumn ' Do the following to add schema. dataValues = sr.ReadLine().Split(","c) ' For each token in the comma-delimited string, add a column ' to the DataTable schema. Dim token As String For Each token In dataValues col = New DataColumn(token, System.Type.GetType("System.String")) data.Columns.Add(col) Next token ' Do not add the first row as data if the CSV file includes column names. If Not IncludesColumnNames Then data.Rows.Add(CopyRowData(dataValues, data.NewRow())) End If ' Do the following to add data. Dim s As String Do s = sr.ReadLine() If Not s Is Nothing Then dataValues = s.Split(","c) data.Rows.Add(CopyRowData(dataValues, data.NewRow())) End If Loop Until s Is Nothing Finally sr.Close() End Try data.AcceptChanges() Dim dataView As New DataView(data) If Not selectArgs.SortExpression Is String.Empty Then dataView.Sort = selectArgs.SortExpression End If dataList = dataView Else Throw New System.Configuration.ConfigurationErrorsException("File not found, " + Me.SourceFile) End If If dataList is Nothing Then Throw New InvalidOperationException("No data loaded from data source.") End If Return dataList End Function 'ExecuteSelect Private Function CopyRowData([source]() As String, target As DataRow) As DataRow Try Dim i As Integer For i = 0 To [source].Length - 1 target(i) = [source](i) Next i Catch iore As IndexOutOfRangeException ' There are more columns in this row than ' the original schema allows. Stop copying ' and return the DataRow. Return target End Try Return target End Function 'CopyRowData ' The CsvDataSourceView does not currently ' permit deletion. You can modify or extend ' this sample to do so. Public Overrides ReadOnly Property CanDelete() As Boolean Get Return False End Get End Property Protected Overrides Function ExecuteDelete(keys As IDictionary, values As IDictionary) As Integer Throw New NotSupportedException() End Function 'ExecuteDelete ' The CsvDataSourceView does not currently ' permit insertion of a new record. You can ' modify or extend this sample to do so. Public Overrides ReadOnly Property CanInsert() As Boolean Get Return False End Get End Property Protected Overrides Function ExecuteInsert(values As IDictionary) As Integer Throw New NotSupportedException() End Function 'ExecuteInsert ' The CsvDataSourceView does not currently ' permit update operations. You can modify or ' extend this sample to do so. Public Overrides ReadOnly Property CanUpdate() As Boolean Get Return False End Get End Property Protected Overrides Function ExecuteUpdate(keys As IDictionary, _ values As IDictionary, _ oldValues As IDictionary) As Integer Throw New NotSupportedException() End Function 'ExecuteUpdate End Class 'CsvDataSourceView End Namespace
using System; using System.Collections; using System.Data; using System.IO; using System.Security.Permissions; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; // The CsvDataSource is a data source control that retrieves its // data from a comma-separated value file. [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)] public class CsvDataSource : DataSourceControl { public CsvDataSource() : base() {} // The comma-separated value file to retrieve data from. public string FileName { get { return ((CsvDataSourceView)this.GetView(String.Empty)).SourceFile; } set { // Only set if it is different. if ( ((CsvDataSourceView)this.GetView(String.Empty)).SourceFile != value) { ((CsvDataSourceView)this.GetView(String.Empty)).SourceFile = value; RaiseDataSourceChangedEvent(EventArgs.Empty); } } } // Do not add the column names as a data row. Infer columns if the CSV file does // not include column names. public bool IncludesColumnNames { get { return ((CsvDataSourceView)this.GetView(String.Empty)).IncludesColumnNames; } set { // Only set if it is different. if ( ((CsvDataSourceView)this.GetView(String.Empty)).IncludesColumnNames != value) { ((CsvDataSourceView)this.GetView(String.Empty)).IncludesColumnNames = value; RaiseDataSourceChangedEvent(EventArgs.Empty); } } } // Return a strongly typed view for the current data source control. private CsvDataSourceView view = null; protected override DataSourceView GetView(string viewName) { if (null == view) { view = new CsvDataSourceView(this, String.Empty); } return view; } // The ListSourceHelper class calls GetList, which // calls the DataSourceControl.GetViewNames method. // Override the original implementation to return // a collection of one element, the default view name. protected override ICollection GetViewNames() { ArrayList al = new ArrayList(1); al.Add(CsvDataSourceView.DefaultViewName); return al as ICollection; } } // The CsvDataSourceView class encapsulates the // capabilities of the CsvDataSource data source control. public class CsvDataSourceView : DataSourceView { public CsvDataSourceView(IDataSource owner, string name) :base(owner, DefaultViewName) { } // The data source view is named. However, the CsvDataSource // only supports one view, so the name is ignored, and the // default name used instead. public static string DefaultViewName = "CommaSeparatedView"; // The location of the .csv file. private string sourceFile = String.Empty; internal string SourceFile { get { return sourceFile; } set { // Use MapPath when the SourceFile is set, so that files local to the // current directory can be easily used. string mappedFileName = HttpContext.Current.Server.MapPath(value); sourceFile = mappedFileName; } } // Do not add the column names as a data row. Infer columns if the CSV file does // not include column names. private bool columns = false; internal bool IncludesColumnNames { get { return columns; } set { columns = value; } } // Get data from the underlying data source. // Build and return a DataView, regardless of mode. protected override IEnumerable ExecuteSelect(DataSourceSelectArguments selectArgs) { IEnumerable dataList = null; // Open the .csv file. if (File.Exists(this.SourceFile)) { DataTable data = new DataTable(); // Open the file to read from. using (StreamReader sr = File.OpenText(this.SourceFile)) { // Parse the line string s = ""; string[] dataValues; DataColumn col; // Do the following to add schema. dataValues = sr.ReadLine().Split(','); // For each token in the comma-delimited string, add a column // to the DataTable schema. foreach (string token in dataValues) { col = new DataColumn(token,typeof(string)); data.Columns.Add(col); } // Do not add the first row as data if the CSV file includes column names. if (! IncludesColumnNames) data.Rows.Add(CopyRowData(dataValues, data.NewRow())); // Do the following to add data. while ((s = sr.ReadLine()) != null) { dataValues = s.Split(','); data.Rows.Add(CopyRowData(dataValues, data.NewRow())); } } data.AcceptChanges(); DataView dataView = new DataView(data); if (selectArgs.SortExpression != String.Empty) { dataView.Sort = selectArgs.SortExpression; } dataList = dataView; } else { throw new System.Configuration.ConfigurationErrorsException("File not found, " + this.SourceFile); } if (null == dataList) { throw new InvalidOperationException("No data loaded from data source."); } return dataList; } private DataRow CopyRowData(string[] source, DataRow target) { try { for (int i = 0;i < source.Length;i++) { target[i] = source[i]; } } catch (System.IndexOutOfRangeException) { // There are more columns in this row than // the original schema allows. Stop copying // and return the DataRow. return target; } return target; } // The CsvDataSourceView does not currently // permit deletion. You can modify or extend // this sample to do so. public override bool CanDelete { get { return false; } } protected override int ExecuteDelete(IDictionary keys, IDictionary values) { throw new NotSupportedException(); } // The CsvDataSourceView does not currently // permit insertion of a new record. You can // modify or extend this sample to do so. public override bool CanInsert { get { return false; } } protected override int ExecuteInsert(IDictionary values) { throw new NotSupportedException(); } // The CsvDataSourceView does not currently // permit update operations. You can modify or // extend this sample to do so. public override bool CanUpdate { get { return false; } } protected override int ExecuteUpdate(IDictionary keys, IDictionary values, IDictionary oldValues) { throw new NotSupportedException(); } }

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
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