Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / UI / DataSourceSelectArguments.cs / 1 / DataSourceSelectArguments.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Web.UI { using System.Diagnostics; using System.Security.Permissions; [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] public sealed class DataSourceSelectArguments { private DataSourceCapabilities _requestedCapabilities; private DataSourceCapabilities _supportedCapabilities; private int _maximumRows; private bool _retrieveTotalRowCount; private string _sortExpression; private int _startRowIndex; private int _totalRowCount = -1; public DataSourceSelectArguments() : this(String.Empty, 0, 0) { } public DataSourceSelectArguments(string sortExpression) : this(sortExpression, 0, 0) { } public DataSourceSelectArguments(int startRowIndex, int maximumRows) : this(String.Empty, startRowIndex, maximumRows) { } public DataSourceSelectArguments(string sortExpression, int startRowIndex, int maximumRows) { SortExpression = sortExpression; StartRowIndex = startRowIndex; MaximumRows = maximumRows; } // Empty cannot be a static readonly field because we want each requester to get their own copy. // This is because DataSourceViews need to call AddSupportedCapabilities on the DataSourceSelectArguments, // changing it to be suited to the DataSourceView's needs. If another DataSourceView used the same instance, // the supported capabilities would be wrong. This member stays as a property for programming ease and // returns a new instance each time. If the user wants to change this instance, they're free to. public static DataSourceSelectArguments Empty { get { return new DataSourceSelectArguments(); } } ////// The maximum number of rows requested for a paged data request. /// Use 0 to indicate all rows. /// public int MaximumRows { get { return _maximumRows; } set { if (value == 0) { if (_startRowIndex == 0) { _requestedCapabilities &= ~DataSourceCapabilities.Page; } } else { _requestedCapabilities |= DataSourceCapabilities.Page; } _maximumRows = value; } } ////// Indicates whether the total row count is requested /// public bool RetrieveTotalRowCount { get { return _retrieveTotalRowCount; } set { if (value) { _requestedCapabilities |= DataSourceCapabilities.RetrieveTotalRowCount; } else { _requestedCapabilities &= ~DataSourceCapabilities.RetrieveTotalRowCount; } _retrieveTotalRowCount = value; } } ////// The expression used to sort the data. /// public string SortExpression { get { if (_sortExpression == null) _sortExpression = String.Empty; return _sortExpression; } set { if (String.IsNullOrEmpty(value)) { _requestedCapabilities &= ~DataSourceCapabilities.Sort; } else { _requestedCapabilities |= DataSourceCapabilities.Sort; } _sortExpression = value; } } ////// The index of the first row requested for a paged data request /// public int StartRowIndex { get { return _startRowIndex; } set { if (value == 0) { if (_maximumRows == 0) { _requestedCapabilities &= ~DataSourceCapabilities.Page; } } else { _requestedCapabilities |= DataSourceCapabilities.Page; } _startRowIndex = value; } } ////// The number of rows returned by the query that counts the number of rows. Typically /// set by the DataSource. /// public int TotalRowCount { get { return _totalRowCount; } set { _totalRowCount = value; } } ////// DataSource controls would call this for each capability that it handled. /// It would do the bitwise operations to handle determining what capabilities were left /// over at the end for RaiseUnsupportedCapabilitiesError to handle. /// public void AddSupportedCapabilities(DataSourceCapabilities capabilities) { _supportedCapabilities |= capabilities; } ////// Prevents a compiler error because Equals was overridden /// public override int GetHashCode() { return System.Web.Util.HashCodeCombiner.CombineHashCodes(_maximumRows.GetHashCode(), _retrieveTotalRowCount.GetHashCode(), _sortExpression.GetHashCode(), _startRowIndex.GetHashCode(), _totalRowCount.GetHashCode()); } public override bool Equals(object obj) { DataSourceSelectArguments arguments = obj as DataSourceSelectArguments; if (arguments != null) { return ((arguments.MaximumRows == _maximumRows) && (arguments.RetrieveTotalRowCount == _retrieveTotalRowCount) && (arguments.SortExpression == _sortExpression) && (arguments.StartRowIndex == _startRowIndex) && (arguments.TotalRowCount == _totalRowCount)); } return false; } ////// Select implementations would call this method to raise errors on unsupported capabilities. /// public void RaiseUnsupportedCapabilitiesError(DataSourceView view) { DataSourceCapabilities unsupportedCapabilities; unsupportedCapabilities = _requestedCapabilities & ~_supportedCapabilities; if ((unsupportedCapabilities & DataSourceCapabilities.Sort) != 0) { view.RaiseUnsupportedCapabilityError(DataSourceCapabilities.Sort); } if ((unsupportedCapabilities & DataSourceCapabilities.Page) != 0) { view.RaiseUnsupportedCapabilityError(DataSourceCapabilities.Page); } if ((unsupportedCapabilities & DataSourceCapabilities.RetrieveTotalRowCount) != 0) { view.RaiseUnsupportedCapabilityError(DataSourceCapabilities.RetrieveTotalRowCount); } Debug.Assert(unsupportedCapabilities == 0, "unknown capability not supported"); } } }
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