Dialog Box Run-time error in ArcObjects

Question

I am trying to open a dialog box which shows up only raster datasets so that I can select one and create Hill shade based on it. But I am facing a run time error for Dialog box when I click on the addin button. Could any one please help me out regarding this

Protected Overrides Sub OnClick()
    '
    '  TODO: Sample code showing how to access button host
    '
    My.ArcMap.Application.CurrentTool = Nothing

    Dim pMxDoc As IMxDocument = My.ArcMap.Document
    Dim pMap As IMap = pMxDoc.FocusMap
    Dim bObjectSelected As Boolean
    Dim pGxDialog As IGxDialog = New GxDialog
    'only show raster datasets
    Dim pRasterFilter As IGxObjectFilter = New GxFilterRasterDatasets
    'Layers and document declaration
    Dim pGxObjects As IEnumGxObject = Nothing
    Dim pGxDataset As IGxDataset
    Dim pRasterLayer As IRasterLayer

    Try
        With pGxDialog
            .AllowMultiSelect = False
            .StartingLocation = "C:\Users\rxm160030\Downloads\Lab12\Data"
            .Title = "Select Raster datasets to Add to Map"
            .ObjectFilter = pRasterFilter
            .DoModalOpen(My.ArcMap.Application.hWnd, pGxObjects)
        End With

        'If no file selected, exit
        If bObjectSelected = Nothing Then Exit Sub

        'Get first dataset
        pGxDataset = pGxObjects.Next
        'no dataset selected
        If pGxDataset Is Nothing Then Exit Sub
        'iterate through remaining datasets
        Do Until pGxDataset Is Nothing
            pRasterLayer = New RasterLayer
            'assign dataset to rasterLayer
            Dim pInputRaster As IRaster = pRasterLayer.Raster
            'assign dataset name to rasterLayer
            pRasterLayer.Name = pGxDataset.Dataset.Name
            ' Do something with the featureLayer
            Dim choice1 As String = InputBox("Enter Azimuth")
            Dim choice2 As String = InputBox("Enter Altitude")

            Dim pSurfaceOp As ISurfaceOp = New RasterSurfaceOp
            Dim pEnv As IRasterAnalysisEnvironment = pSurfaceOp
            Dim pWSF As IWorkspaceFactory = New RasterWorkspaceFactory
            Dim pWS As IWorkspace = pWSF.OpenFromFile("C:\Users\rxm160030\Downloads\Lab12\Data", 0)
            pEnv.OutWorkspace = pWS
            Dim pOutput As IGeoDataset = pSurfaceOp.HillShade(pInputRaster, choice1, choice2, True)

            Dim pOutLayer As IRasterLayer = New RasterLayer
            pOutLayer.CreateFromRaster(pOutput)
            pOutLayer.Name = "HillShade"
            pMap.AddLayer(pRasterLayer)
            pMap.AddLayer(pOutLayer)
            ' Go to next dataset
            pGxDataset = pGxObjects.Next
        Loop
    Catch ex As Exception
        MsgBox("BtnAdd_Click Exception: " & ex.Message)
    Finally
        ' Release ArcObjects objects
        pGxObjects = Nothing
        pRasterFilter = Nothing
        pGxDialog = Nothing
        pGxDataset = Nothing
        pRasterLayer = Nothing
        ' Call garbage collection
        GC.Collect()
        GC.WaitForPendingFinalizers()
    End Try
    pMxDoc.ActiveView.PartialRefresh(esriViewGeography, Nothing, Nothing)
End Sub

Answer 1

The code you have should work but it looks like the references are messed up. Instead of referencing ESRI.ArcGIS.CatalogUI it is setting your dialog object to a type from Lab12_Q2.dll. Try explicitly telling it to use ESRI.ArcGIS.CatalogUI by writing that line of code this way:

Dim pGxDialog As ESRI.ArcGIS.CatalogUI.IGxDialog = New ESRI.ArcGIS.CatalogUI.GxDialog

Answer 2

First, have you tried an explicit cast from (new GxDialog) to IGxDialog. I definitely encounter situations where the I have to explicitly cast to the interface to get things working.

Secondly, I would expect these types to reside in ESRI.ArcGIS.CatalogUI reference. Is that reference included in your current project?