How to hatch all features in a layer

Public Sub Hatches()
    
    '+++ Get the polyine (with measures) layer and its hatch layer extension.
    Dim pMxDoc As IMxDocument
    Dim pMap As IMap
    Dim pLayerExt As ILayerExtensions
    Dim pLayer As ILayer
    Dim pFLayer As IFeatureLayer
    Dim i As Long
    
    Set pMxDoc = Application.Document
    Set pMap = pMxDoc.FocusMap
    For i = 0 To pMap.LayerCount - 1
        Set pLayer = pMap.Layer(i)
        If pLayer.Name = "Hatches" Then 'Assume the layer name is "hatches"
            If TypeOf pLayer Is IFeatureLayer Then
                Set pFLayer = pLayer
                Exit For
            End If
        End If
    Next i
    If pFLayer Is Nothing Then
        MsgBox "Could not find the polyline feature with measure (Ms) layer.", vbExclamation, ""
        Exit Sub
    End If
    
    
    '+++ Some symbology to be used later.
    Dim pLineSymbol As ILineSymbol
    Dim pTextSymbol As ITextSymbol
    Dim pColor As IColor
    Set pLineSymbol = New SimpleLineSymbol
    Set pTextSymbol = New TextSymbol
    pTextSymbol.Size = 8
    Set pColor = New RgbColor
    pColor.RGB = RGB(255, 25, 15)
    pTextSymbol.Color = pColor
    pTextSymbol.HorizontalAlignment = esriTHALeft
    pTextSymbol.VerticalAlignment = esriTVACenter
    
    
    '+++ Get the hatch layer extension that is automatically attached to the layer by ArcMap.
    Dim pHatchLayerExt As IHatchLayerExtension
    Set pLayerExt = pFLayer
    For i = 0 To pLayerExt.ExtensionCount - 1
        If TypeOf pLayerExt.Extension(i) Is IHatchLayerExtension Then
            Set pHatchLayerExt = pLayerExt.Extension(i)
            Exit For
        End If
    Next i
    If pHatchLayerExt Is Nothing Then
        MsgBox "Could not find hatch layer extension", vbExclamation
        Exit Sub
    End If
    
    
    '+++ The hatch layer extension always maintains a 'default' hatch class. The following code
    '+++ simply gets rid of any existing hatch classes.
    pHatchLayerExt.RemoveAll
    
    
    '+++ The following code will place a hatch every 0.25 miles. Every fourth hatch
    '+++ will be labeled. Lastly, each line will have special hatches at their ends.
    
    '+++ To do this, we must create a hatch class. A hatch class has a hatch template.
    '+++ Each hatch template is composed of one or more hatch definitions. A hatch definition
    '+++ may or may not be labeled. To place hatches at the ends of a line, you use an end hatch
    '+++ definition. A hatch template can only have one end hatch definition.
    
    '+++ A layer can have more than one hatch class attached to it. This is
    '+++ useful when you want to hatch different features in different ways or
    '+++ if you want to hatch features differently, depending on the map's scale.
    '+++ Create a hatch class and indicate its interval. We will assign a template to it later.
    Dim pHatchClass As IHatchClass
    Set pHatchClass = New HatchClass
    
    
    '+++ Set the hatch interval for the hatch class.
    Dim pHatchInput As IHatchInputValue
    Set pHatchInput = New HatchInputValue
    pHatchInput.Value = 0.25
    Set pHatchClass.HatchInterval = pHatchInput
    
    
    '+++ Create a hatch template. We will assign the definitions to it later.
    Dim pHatchTemplate As IHatchTemplate
    Set pHatchTemplate = New HatchTemplate
    
    
    'Create the first hatch definition. It will not have labels.
    Dim pHatchDef1 As IHatchDefinition
    Dim pHatchLineDef1 As IHatchLineDefinition 'or IHatchMarkerDefinition.
    Set pHatchDef1 = New HatchLineDefinition 'or HatchMarkerDefinition.
    Set pHatchDef1.HatchSymbol = pLineSymbol
    Set pHatchLineDef1 = pHatchDef1
    pHatchLineDef1.Length = 500 'specified in the xy units of the feature class's spatial reference.
    
    
    '+++ Create the second hatch definition (with labels).
    Dim pHatchDef2 As IHatchDefinition
    Dim pHatchLineDef12 As IHatchLineDefinition
    Set pHatchDef2 = New HatchLineDefinition
    With pHatchDef2
        Set .HatchSymbol = pLineSymbol
        .TextDisplay = esriHatchTDValueOnly
        Set .TextSymbol = pTextSymbol
        .DisplayPrecision = 1
    End With
    Set pHatchLineDef12 = pHatchDef2
    pHatchLineDef12.Length = pHatchLineDef1.Length * 1.5
    
    
    '+++ Create end hatches (with labels). We will copy the properties from the second hatch def.
    Dim pClone As IClone
    Dim pEndsHatchDef As IHatchDefinition
    Set pClone = pHatchDef2
    Set pEndsHatchDef = pClone.Clone
    
    
    '+++ Add the hatch definitions to the hatch template.
    With pHatchTemplate
        .Name = "HatchTemplate1"
        .AddHatchDefinition 1, pHatchDef1
        .AddHatchDefinition 4, pHatchDef2
        Set .EndHatchDefinition = pEndsHatchDef
        .EndHatchDrawingTolerance = 0.2 'No hatch will be placed if it is within 0.2 measure units of the end.
        .StartAtIntervalMultiple = True
    End With
    
    
    '+++ Apply the template to the hatch class. Even though they are not done here, you can also do the
    '+++ following with a hatch class:
    '+++      - specify a query filter to limit the features that are hatched
    '+++      - specify start and finish values to limit the portions of features that are hatched
    '+++      - specify a minimum and maximum scale at which hatches will be displayed
    '+++      - offset all of the hatch definitions in the hatch class (this is different than offsetting
    '+++        the individual hatch definitions.
    Set pHatchClass.HatchTemplate = pHatchTemplate
    
    
    '+++ Add the hatch class to the hatch layer extension.
    pHatchLayerExt.AddClass "Class1", pHatchClass
    pHatchLayerExt.ShowHatches = True 'Show the hatch class(es)
    '+++ Refresh the map document.
    pMxDoc.ActiveView.Refresh
    
End Sub