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//------------------------------------------------------------------------------
// <copyright file="DataSourceSelectArguments.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.UI {
using System.Diagnostics;
using System.Security.Permissions;
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();
}
}
/// <devdoc>
/// The maximum number of rows requested for a paged data request.
/// Use 0 to indicate all rows.
/// </devdoc>
public int MaximumRows {
get {
return _maximumRows;
}
set {
if (value == 0) {
if (_startRowIndex == 0) {
_requestedCapabilities &= ~DataSourceCapabilities.Page;
}
}
else {
_requestedCapabilities |= DataSourceCapabilities.Page;
}
_maximumRows = value;
}
}
/// <devdoc>
/// Indicates whether the total row count is requested
/// </devdoc>
public bool RetrieveTotalRowCount {
get {
return _retrieveTotalRowCount;
}
set {
if (value) {
_requestedCapabilities |= DataSourceCapabilities.RetrieveTotalRowCount;
}
else {
_requestedCapabilities &= ~DataSourceCapabilities.RetrieveTotalRowCount;
}
_retrieveTotalRowCount = value;
}
}
/// <devdoc>
/// The expression used to sort the data.
/// </devdoc>
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;
}
}
/// <devdoc>
/// The index of the first row requested for a paged data request
/// </devdoc>
public int StartRowIndex {
get {
return _startRowIndex;
}
set {
if (value == 0) {
if (_maximumRows == 0) {
_requestedCapabilities &= ~DataSourceCapabilities.Page;
}
}
else {
_requestedCapabilities |= DataSourceCapabilities.Page;
}
_startRowIndex = value;
}
}
/// <devdoc>
/// The number of rows returned by the query that counts the number of rows. Typically
/// set by the DataSource.
/// </devdoc>
public int TotalRowCount {
get {
return _totalRowCount;
}
set {
_totalRowCount = value;
}
}
/// <devdoc>
/// 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.
/// </devdoc>
public void AddSupportedCapabilities(DataSourceCapabilities capabilities) {
_supportedCapabilities |= capabilities;
}
/// <devdoc>
/// Prevents a compiler error because Equals was overridden
/// </devdoc>
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;
}
/// <devdoc>
/// Select implementations would call this method to raise errors on unsupported capabilities.
/// </devdoc>
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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