111 lines
3.2 KiB
C#
111 lines
3.2 KiB
C#
namespace System.Web.UI.WebControls {
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/// <summary>
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/// This class tracks the values of SelectMethod parameters of ModelDataSourceView that use a custom value provider across multiple page requests.
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/// </summary>
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internal sealed class MethodParameterValue : IStateManager {
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private MethodParametersDictionary _owner;
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private bool _tracking;
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private StateBag _viewState;
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private static readonly string s_valueViewStateKey = "ParameterValue";
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/// <devdoc>
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/// Tells the Parameter the dictionary it belongs to
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/// </devdoc>
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internal void SetOwner(MethodParametersDictionary owner) {
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_owner = owner;
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}
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/// <devdoc>
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/// Raises the ParameterChanged event.
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/// </devdoc>
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private void OnParameterChanged() {
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if (_owner != null) {
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_owner.CallOnParametersChanged();
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}
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}
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internal void UpdateValue(object newValue) {
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object oldValue = ViewState[s_valueViewStateKey];
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ViewState[s_valueViewStateKey] = newValue;
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if ((newValue == null && oldValue != null) || (newValue != null && !newValue.Equals(oldValue))) {
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OnParameterChanged();
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}
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}
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/// <devdoc>
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/// Indicates whether the MethodParameter is tracking view state.
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/// </devdoc>
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private bool IsTrackingViewState {
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get {
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return _tracking;
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}
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}
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/// <devdoc>
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/// Indicates a dictionary of state information that allows you to save and restore
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/// the state of a MethodParameter across multiple requests for the same page.
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/// </devdoc>
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private StateBag ViewState {
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get {
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if (_viewState == null) {
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_viewState = new StateBag();
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if (_tracking)
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_viewState.TrackViewState();
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}
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return _viewState;
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}
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}
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/// <devdoc>
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/// Loads view state.
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/// </devdoc>
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private void LoadViewState(object savedState) {
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if (savedState != null) {
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ViewState.LoadViewState(savedState);
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}
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}
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/// <devdoc>
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/// Saves view state.
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/// </devdoc>
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private object SaveViewState() {
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return (_viewState != null) ? _viewState.SaveViewState() : null;
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}
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/// <devdoc>
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/// Tells the MethodParameter to start tracking property changes.
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/// </devdoc>
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private void TrackViewState() {
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_tracking = true;
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if (_viewState != null) {
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_viewState.TrackViewState();
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}
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}
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#region Implementation of IStateManager
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bool IStateManager.IsTrackingViewState {
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get {
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return IsTrackingViewState;
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}
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}
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void IStateManager.LoadViewState(object savedState) {
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LoadViewState(savedState);
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}
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object IStateManager.SaveViewState() {
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return SaveViewState();
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}
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void IStateManager.TrackViewState() {
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TrackViewState();
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}
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#endregion
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}
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}
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