ISpatialFilter Example with Description

Here I am Explaining the use of ISpatialFilter Interface
Add a custom UIToolControl onto any toolbar and make sure the names of the control match the code. This sample assumes the control is called UIToolControl1.
Paste the code into VBA.
Select the tool and then click on a feature.
Private Sub UIToolControl1_MouseDown(ByVal button As Long, ByVal shift As Long, ByVal x As Long, ByVal y As Long)
Dim pMxDoc As IMxDocument
Dim pActiveView As IActiveView
Dim pPoint As IPoint
Dim pFeature As IFeature

Set pMxDoc = Application.Document
Set pActiveView = pMxDoc.FocusMap
'Create a search point
Set pPoint = pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y)
'Pass the point to the FindFeature function along with the Map and search tolerance
Set pFeature = FindFeature(pMxDoc.SearchTolerance, pPoint, pMxDoc.FocusMap)
'Message box the feature ID and feature class alias name
If Not pFeature Is Nothing Then MsgBox pFeature.OID & " " & pFeature.Class.AliasName
End Sub
Private Function FindFeature(SearchTol As Double, pPoint As IPoint, pMap As IMap) As IFeature
Dim pEnvelope As IEnvelope
Dim pSpatialFilter As ISpatialFilter
Dim pEnumLayer As IEnumLayer
Dim pFeatureLayer As IFeatureLayer
Dim pFeatureClass As IFeatureClass
Dim pFeatureCursor As IFeatureCursor
Dim pFeature As IFeature
Dim pUID As New UID
Dim ShapeFieldName As String

If pMap.LayerCount = 0 Then Exit Function

'Expand the points envelope to give better search results
Set pEnvelope = pPoint.Envelope
pEnvelope.Expand SearchTol, SearchTol, False

'Create a new spatial filter and use the new envelope as the geometry
Set pSpatialFilter = New SpatialFilter
Set pSpatialFilter.Geometry = pEnvelope
pSpatialFilter.SpatialRel = esriSpatialRelIntersects
'Search each selectable feature layer for a feature
'Return the first feature found
pUID = "{40A9E885-5533-11D0-98BE-00805F7CED21}" 'IFeatureLayer
Set pEnumLayer = pMap.Layers(pUID, False)
pEnumLayer.Reset
Set pFeatureLayer = pEnumLayer.Next
Do While Not pFeatureLayer Is Nothing
'Only search the selectable layers
If pFeatureLayer.Selectable Then
ShapeFieldName = pFeatureLayer.FeatureClass.ShapeFieldName
Set pSpatialFilter.OutputSpatialReference(ShapeFieldName) = pMap.SpatialReference
pSpatialFilter.GeometryField = pFeatureLayer.FeatureClass.ShapeFieldName
Set pFeatureClass = pFeatureLayer.FeatureClass
Set pFeatureCursor = pFeatureClass.Search(pSpatialFilter, False) 'Do the search
Set pFeature = pFeatureCursor.NextFeature 'Get the first feature
If Not pFeature Is Nothing Then
Set FindFeature = pFeature 'Exit if feature is valid
Exit Do
End If
End If
Set pFeatureLayer = pEnumLayer.Next
Loop
End Function