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IFilterProvider.ClearFilter Event

NOTE: This API is now obsolete.

Notifies the consumer Web Part to clear the current filter.

Namespace:  Microsoft.SharePoint.WebPartPages.Communication
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)

Syntax

<ObsoleteAttribute("Use System.Web.UI.WebControls.WebParts.IWebPartParameters instead")> _
Event ClearFilter As ClearFilterEventHandler

Dim instance As IFilterProvider
Dim handler As ClearFilterEventHandler

AddHandler instance.ClearFilter, handler
[ObsoleteAttribute("Use System.Web.UI.WebControls.WebParts.IWebPartParameters instead")]
event ClearFilterEventHandler ClearFilter

Examples

The following code example shows an overridden PartCommunicationMainmethod that fires the ClearFilter event. This code example is part of a larger example provided for the IFilterProvider interface.

      ' Step #7: Override the PartCommunicationMain() method.
      ' The PartCommunicationMain method is called by the Web Part 
      ' infrastucture on the client during the ASP.NET PreRender
      ' event to allow the part to pass its primary data to the other 
      ' connected parts.
      ' It is important to always fire either the SetFilter, NoFilter, 
      ' or ClearFilter event. Some parts
      ' may not behave properly if they are left waiting for this 
      ' information.
      ' SetFilter should be fired to send the filter expression.
      ' NoFilter should be fired to indicate that there is no change in 
      ' the filter expression.
      ' ClearFilter should be fired to indicate that the filter should 
      ' be removed.
      Public Overrides Sub PartCommunicationMain()
            ' Ensure that all of the Web Part's controls are created.
            EnsureChildControls()

            ' Check if connected.
            If _connected Then
                ' Check which button was clicked.
                If _setFilterClicked = True Then
                    ' Create the SetFilterEventArgs object for the 
                    ' SetFilter event.
                    Dim setFilterEventArgs As New SetFilterEventArgs()

                    ' Create the filter expression.
                    Dim eIndex As Integer = 1
                    Dim filterExpression As String = String.Empty
                    Dim index As Integer
                    For index = 0 To _fieldList.Length - 1
                        ' This filter expression syntax should be used 
                        ' with SharePoint Lists
                        ' and other Microsoft Web Parts that support 
                        ' the IFilterConsumer interface.
                        If _filterInputs(index).Text <> String.Empty 
                        Then
                            filterExpression += FieldLabel + 
                               eIndex.ToString() + "=" + 
                               _fieldList(index) + "&"
                            filterExpression += ValueLabel + 
                               eIndex.ToString() + "=" + 
                               _filterInputs(index).Text + "&"
                            eIndex += 1
                        End If
                    Next index

                    ' Trim Off Trailing '&'
                    If filterExpression.Length <> 0 Then
                        filterExpression = filterExpression.Substring(0, filterExpression.Length - 1)
                    End If
                    ' Set the FilterExpression property on the 
                    ' SetFilterEventArgs object.
                    setFilterEventArgs.FilterExpression = 
                       filterExpression

                    ' Set the _filterExpression variable for display in 
                    ' the user interface.
                    _filterExpression = filterExpression

                    ' Fire the event.
                    RaiseEvent SetFilter(Me, setFilterEventArgs)
                    _setFilterClicked = False

                ElseIf _clearFilterClicked = True Then
                    RaiseEvent ClearFilter(Me, New EventArgs())
                    _clearFilterClicked = False

                    ' Clear out values in input text boxes.
                    If Not (_filterInputs Is Nothing) Then
                        Dim index As Integer
                        For index = 0 To _filterInputs.Length - 1
                            _filterInputs(index).Text = String.Empty
                        Next index
                    End If
                ElseIf _noFilterClicked = True Then
                    RaiseEvent NoFilter(Me, New EventArgs())
                    _noFilterClicked = False
                Else
                    RaiseEvent NoFilter(Me, New EventArgs())
                End If
            End If
        End Sub
// Step #7: Override the PartCommunicationMain() method.
// The PartCommunicationMain method is called by the Web Part 
// infrastructure on the client during the ASP.NET PreRender
// event to allow the part to pass its primary data to the other 
// connected parts.
// It is important to always fire either the SetFilter, NoFilter, or 
// ClearFilter event. Some parts
// may not behave properly if they are left waiting for this 
// information.
// SetFilter should be fired to send the filter expression.
// NoFilter should be fired to indicate that there is no change in the 
// filter expression.
// ClearFilter should be fired to indicate that the filter should be 
// removed.

public override void PartCommunicationMain()
{
    // Ensure that all of the Web Part's controls are created.
    EnsureChildControls();

    // Check if connected.
    if(_connected)
    {
        // Check which button was clicked.
        if(_setFilterClicked == true)
        {
            // If there is a listener, fire the SetFilter event.
            if (SetFilter != null)
            {
                // Create the SetFilterEventArgs object for the 
                // SetFilter event.
                SetFilterEventArgs setFilterEventArgs = new 
                   SetFilterEventArgs();

                // Create the filter expression.
                int eIndex = 1;
                string filterExpression = string.Empty;
                for (int index = 0; index < _fieldList.Length; index++)
                {
                    // This filter expression syntax should be used 
                    // with SharePoint lists
                    // and other Microsoft Web Parts that support the 
                    // IFilterConsumer interface.
                    if (_filterInputs[index].Text != string.Empty)
                    {
                        filterExpression += FieldLabel + 
                           eIndex.ToString() + "=" + 
                           _fieldList[index] + "&";
                        filterExpression += ValueLabel + 
                           eIndex.ToString() + "=" + 
                           _filterInputs[index].Text + "&";
                        eIndex++;
                    }
                }

                // Trim Off Trailing '&'
                if (filterExpression.Length != 0)
                    filterExpression = filterExpression.Substring(0,filterExpression.Length - 1);
                // Set the FilterExpression property on the 
                // SetFilterEventArgs object.
                setFilterEventArgs.FilterExpression = filterExpression;

                // Set the _filterExpression variable for display in 
                // the user interface.
                _filterExpression = filterExpression;

                // Fire the event.
                SetFilter(this, setFilterEventArgs);

                _setFilterClicked = false;
            }
        }
        else if(_clearFilterClicked == true)
        {
            // If there is a listener, fire the ClearFilter event.
            if (ClearFilter != null)
            {
                ClearFilter(this, new EventArgs());

                _clearFilterClicked = false;

                // Clear out values in input text boxes.
                if (_filterInputs != null)
                {
                    for (int index = 0; index < _filterInputs.Length; 
                       index++)
                        _filterInputs[index].Text = string.Empty;
                }
            }
        }
        else if(_noFilterClicked == true)
        {
            // If there is a listener, fire the NoFilter event.
            if (NoFilter != null)
            {
                NoFilter(this, new EventArgs());

                _noFilterClicked = false;
            }
        }
        else
        {
            // If there is a listner, fire the NoFilter event.
            if (NoFilter != null)
            {
                NoFilter(this, new EventArgs());
            }
        }
    }
}

See Also

Reference

IFilterProvider Interface

IFilterProvider Members

Microsoft.SharePoint.WebPartPages.Communication Namespace