直接上源码，供大家一看

  ''' <summary>
  ''' 根据某一字段的值用不同的Symbol加以渲染
  ''' </summary>
  ''' <param name="pGeoFeatureLayer">渲染的Layer</param>
  ''' <remarks></remarks>
  Private Sub UniqueRender(ByVal pGeoFeatureLayer As IGeoFeatureLayer)
    Dim pUniqueRender As IUniqueValueRenderer = New UniqueValueRenderer
    Dim pColor As IColor
    Dim pCMSymbol As ICharacterMarkerSymbol
    Dim pFont As stdole.IFontDisp = New stdole.StdFont
    pFont.Name = "ESRI Default Marker"
    pColor = New RgbColor
    pColor.RGB = RGB(56, 168, 0)
    pCMSymbol = New CharacterMarkerSymbol
    pCMSymbol.Font = pFont
    pCMSymbol.CharacterIndex = 33
    pCMSymbol.Color = pColor
    pCMSymbol.Size = 10
    pUniqueRender.FieldCount = 1
    pUniqueRender.Field(0) = g_FieldType
    pUniqueRender.DefaultSymbol = pCMSymbol
    pUniqueRender.UseDefaultSymbol = True

    pColor = New RgbColor
    pColor.RGB = RGB(255, 255, 0)
    pCMSymbol = New CharacterMarkerSymbol
    pCMSymbol.Font = pFont
    pCMSymbol.CharacterIndex = 80
    pCMSymbol.Color = pColor
    pCMSymbol.Size = 20
    ''添加的不同类型，其中featureclass中必须有与之对应的字段
    pUniqueRender.AddValue(2, "Type1", pCMSymbol)

    pColor = New RgbColor
    pColor.RGB = RGB(85, 255, 0)
    pCMSymbol = New CharacterMarkerSymbol
    pCMSymbol.Font = pFont
    pCMSymbol.CharacterIndex = 88
    pCMSymbol.Color = pColor
    pCMSymbol.Size = 20
    pUniqueRender.AddValue(3, "Type2", pCMSymbol)

    pGeoFeatureLayer.Renderer = pUniqueRender
    pGeoFeatureLayer.DisplayField = "Type"    '用于唯一值渲染的字段名
  End Sub