This will add an Integer type field named "Count" to the feature class of a selected feature layer. It is just the basics, but should get you started
Private Sub UIButtonControlAddField_Click()
Dim sToolName As String
sToolName = "Test Add Field"
Dim pMxDoc As IMxDocument
Dim pLayer As ILayer
Dim pFeatureLayer As IFeatureLayer
Dim pFeatureClass As IFeatureClass
Dim pField As IField
Set pMxDoc = Application.Document
Set pLayer = pMxDoc.SelectedLayer
' Make sure some type of layer is selected
If (pLayer Is Nothing) Then
MsgBox "Please Select a feature layer.", vbOKOnly, sToolName
Exit Sub
End If
' Make sure a feature layer (not a group layer) is selected
If Not (TypeOf pLayer Is IFeatureLayer) Then
MsgBox "Please Select a feature layer.", vbOKOnly, sToolName
Exit Sub
End If
Set pFeatureLayer = pMxDoc.SelectedLayer
Set pFeatureClass = pFeatureLayer.featureClass
Set pField = MakeIntField("COUNT")
AddFieldToFeatureClass pFeatureClass, pField
End Sub
Public Function MakeIntField(fieldName As String) As IField
Dim pFieldEdit As IFieldEdit
Dim pField As IField
Set pField = New field
Set pFieldEdit = pField
pFieldEdit.Name = fieldName
pFieldEdit.Type = esriFieldTypeInteger
Set MakeIntField = pField
End Function
Public Sub AddFieldToFeatureClass(featureClass As IFeatureClass, field As IField)
Dim schemaLock As ISchemaLock
On Error GoTo ErrorHandler
Set schemaLock = featureClass
schemaLock.ChangeSchemaLock (esriSchemaLock.esriExclusiveSchemaLock)
featureClass.AddField field
schemaLock.ChangeSchemaLock (esriSchemaLock.esriSharedSchemaLock)
Exit Sub
ErrorHandler:
schemaLock.ChangeSchemaLock (esriSchemaLock.esriSharedSchemaLock)
End Sub
