Option Explicit

Public Sub PopulateStateCombo()
    ' This procedure uses the State layer to populate
    ' cboState with state names. The State layer is available
    ' through a global variable that was set in module Main.
    '
    ' (1) Access the State layer
    Dim pLayer As IFeatureLayer
    Dim pFeatureClass As IFeatureClass
    Set pLayer = Main.g_pStateLayer
    Set pFeatureClass = pLayer.FeatureClass
    '
    ' (2) Sort State layer's table
    Dim pTableSort As ITableSort
    Set pTableSort = New TableSort
    pTableSort.Fields = "STATE_NAME"
    pTableSort.Ascending("STATE_NAME") = True
    Set pTableSort.Table = pFeatureClass
    pTableSort.Sort Nothing
    '
    ' (3) Populate the State's combo box
    Dim pCursor As ICursor
    Dim pRow As IRow
    Dim lngFieldIndex As Long
    Set pCursor = pTableSort.Rows
    lngFieldIndex = pFeatureClass.FindField("STATE_NAME")
    Set pRow = pCursor.NextRow
    Do While Not pRow Is Nothing
        cboState.AddItem pRow.Value(lngFieldIndex)
        Set pRow = pCursor.NextRow
    Loop
    cboState.ListIndex = 0
End Sub

Public Sub PopulateClassificationCombo()
    ' The Classification field combo always has a list
    ' of numeric fields in the census tract layer. This
    ' procedure populates it.
    '
    ' (1) Access the Tract layer
    Dim pLayer As IFeatureLayer
    Dim pFeatureClass As IFeatureClass
    Set pLayer = Main.g_pTractLayer
    Set pFeatureClass = pLayer.FeatureClass
    '
    ' (2) Populate combo box with numeric field names
    Dim pFields As IFields
    Dim pField As IField
    Dim lngIndex As Long
    Set pFields = pFeatureClass.Fields
    For lngIndex = 0 To pFields.FieldCount - 1
        Set pField = pFields.Field(lngIndex)
        If pField.Type = esriFieldTypeDouble Or _
        pField.Type = esriFieldTypeInteger Or _
        pField.Type = esriFieldTypeSingle Then
            cboField.AddItem pField.AliasName
        End If
    Next lngIndex
    cboField.ListIndex = 0
End Sub

Public Sub PopulateClassCountCombo()
    ' The application provides from 2 to 9 classes.
    ' This procedure populates the class count choices
    ' in the class count combo box.
    Dim lngIndex As Long
    For lngIndex = 2 To 9
        cboClassCount.AddItem lngIndex
    Next lngIndex
    cboClassCount.ListIndex = 0
End Sub

Private Sub cboState_Change()
    ' This procedure is executed each time a diffrent
    ' state is selected. It populates the county combo
    ' box based on the selected state.
    '
    ' (1) Access the County layer
    Dim pLayer As IFeatureLayer
    Dim pFeatureClass As IFeatureClass
    Set pLayer = Main.g_pCountyLayer
    Set pFeatureClass = pLayer.FeatureClass
    '
    ' (2) Query and sort County layer's table
    Dim pTableSort As ITableSort
    Dim pQueryFilter As IQueryFilter
    Set pQueryFilter = New QueryFilter
    'pQueryFilter.SubFields = "STATE_NAME,NAME"
    pQueryFilter.WhereClause = "STATE_NAME = '" & _
    cboState.Text & "'"
    Set pTableSort = New TableSort
    pTableSort.Fields = "STATE_NAME,NAME"
    pTableSort.Ascending("STATE_NAME") = True
    pTableSort.Ascending("NAME") = True
    Set pTableSort.QueryFilter = pQueryFilter
    Set pTableSort.Table = pFeatureClass
    pTableSort.Sort Nothing
    '
    ' (3) Populate the County's combo box
    Dim pCursor As ICursor
    Dim pRow As IRow
    Dim lngFieldIndex As Long
    ' Clear any existing county names
    cboCounty.Clear
    Set pCursor = pTableSort.Rows
    lngFieldIndex = pFeatureClass.FindField("NAME")
    Set pRow = pCursor.NextRow
    Do While Not pRow Is Nothing
        cboCounty.AddItem pRow.Value(lngFieldIndex)
        Set pRow = pCursor.NextRow
    Loop
    cboCounty.ListIndex = 0
End Sub

Private Sub cmdCancel_Click()
    End
End Sub

Private Sub cmdOK_Click()
    frmClassify.Hide
    frmLayout.Show
End Sub