Error Checking a Complete Reference Excel Add-in VBA

Error Checking a Complete Reference Excel Add-in VBA

ErrorCheckingOptions

Excel offers Error checking options to trap worksheet errors like Empty Cells Error, Evaluate to error, Inconsistent formula error etc. These errors can be captured by enabling ErrorcheckingOptions in Excel by following below steps or using VBA (Visual Basic for Applications)

Enable Error Checking

  1. Navigate to File menu
  2. Click on Options
  3. Navigate Formula tab
  4. Check necessary Error checking rules as shown below like you can change color for default error in the sheet

Error Rules

Properties

All error options can be trapped from Errors collection object exposed by Range object by iterating Item method which takes a valid constant against each error.

BackgroundChecking

If cell formula pointing to empty cell reference the AutoCorrect option appears in Excel

Code example

Public Sub ErrorBackgroundCheckingOptionsExample()
    
    'Enable background error checking
    Application.ErrorCheckingOptions.BackgroundChecking = True
    
End Sub

Output

EmptyCellReferences

It is similar to Backgroundchecking property but shows Empty cell error under AutoCorrect popup.

Code example

Public Sub EmptyCellReferencesCodeExample()
    
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
       
    'Enable empty cell reference
    Application.ErrorCheckingOptions.EmptyCellReferences = True
    
    If oRange.Errors.Item(xlEmptyCellReferences).Value = True Then
        Debug.Print "Empty cell reference is on"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

Output

EvaluateToError

Excel engine evaluate formulas for the cells containing error. This property enables AutoCorrect option as shown below when set to True.

Code example

Public Sub EvaluateToErrorCodeExample()
    
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Enable background error checking
    Application.ErrorCheckingOptions.EvaluateToError = True
    
    'Check evaluate to error option
    If oRange.Errors.Item(xlEvaluateToError).Value = True Then
        Debug.Print "Evaluate to Error cell reference is on"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

InconsistentFormula

This property helps identifying inconsistency within formulas if sets to True

Public Sub InconsistentFormulaCodeExample()
    
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Enable background error checking
    Application.ErrorCheckingOptions.InconsistentFormula  = True
    
    'Check evaluate to error option
    If oRange.Errors.Item(xlInconsistentFormula).Value = True Then
        Debug.Print "InconsistentFormula cell reference is on"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

Output

IndicatorColorIndex

Takes two constants xlColorIndexAutomatic which indicates default behavior or error checking color indicator and xlColorIndexNone which indicates not color index set.

Code example

Public Sub IndicatorColorIndexCodeExample()
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Validate error checking options color indicator
    If Application.ErrorCheckingOptions.IndicatorColorIndex = xlColorIndexAutomatic Then
        Debug.Print "Error checking color indicator set to Automatic mode"
    Else
        Debug.Print "Error checking color indicator not set"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

NumberAsText

This property helps identifying numbers which are punched as text within a cell when sets to True and enables AutoCorrect popup as shown below

Code example

Public Sub NumberAsTextCodeExample()
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Enable number as text error checking option
    Application.ErrorCheckingOptions.NumberAsText = True
    
    'Validate error checking options Number as text
    If oRange.Errors.Item(xlNumberAsText).Value = True Then
        Debug.Print "Error checking Number as text is On"
    Else
        Debug.Print "Error checking Number as text is Off"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

Output

OmittedCells

Cells which contain such formulas pointing to a range that excludes close or adjacent cells which possibly can be included, AutoCorrect popup gets enabled to help user as shown below where we are doing SUM over B2:B4 and left B5 hence Sum cell shows Omitted Cells error

Code example

Public Sub OmittedCellsCodeExample()
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Enable Omitted Cells error checking option
    Application.ErrorCheckingOptions.OmittedCells = True
    
    'Validate error checking options Omitted Cells
    If oRange.Errors.Item(xlOmittedCells).Value = True Then
        Debug.Print "Error checking Omitted Cells is On"
    Else
        Debug.Print "Error checking Omitted Cells is Off"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

Output

TextDate

This property enables error checking for two digits year within a cell having date when sets to True and enables AutoCorrect popup.

Code example

Public Sub TextDateExample()
    
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Enable Text Date error checking
    Application.ErrorCheckingOptions.TextDate = True
    
    'Check two digits year
    If oRange.Errors.Item(xlTextDate).Value = True Then
        Debug.Print "Text Date error check is on"
    End If
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

Output

UnlockedFormulaCells

This property enables check for unlocked cells having formula when sets to True, enables AutoCorrect popup as shown below in output

Code example

Public Sub UnlockedFormulaCellsExample()
    
    'Declare range object
    Dim oRange As Range
    
    'Bind selection reference object
    Set oRange = Selection
    
    'Enable Text Date error checking
    Application.ErrorCheckingOptions.UnlockedFormulaCells = True
    
    'Lock the cell
    oRange.Locked = False
    
    'Memory cleanup
    Set oRange = Nothing
End Sub

Output

Note: ErrorCheckingOptions object exposed by Application object and most of the properties are boolean type

VBA Error object

Trapping error in VBA depends on the developer what approach he decides. VBA offers two types of error trapping:

  1. In-Line: this trapping trick is used before code execution where user suspects that given statement may result to certain error. Mostly common error trapping which can be used as:
    • On Error Resume Next
  2. Procedure or function level: this error mechanism implements error trapping on entire code block written under a procedure or function using GoTo statement which requires a label or Zero. Commonly used statement as given below which raise a default error determined by VBA compiler:
    • On Error GoTo 0
  3. Centralize Error trapping: Create a common function and call it through all the modules to trap the error

Procedure/Function Error

Public Sub ProcedureLevelErrorTrapping()
    On Error GoTo myError
    
    'code to be executed
    
'Define lable
myError:
'Define Error
If Err.Number <> 0 Then
    Debug.Print Err.Description
End If
End Sub

In above code we have used “myError” label hence whenever code execution encounters an error the control will shift to myError label and evaluate the error. A label must be attached by : (double colon)

Err.Raise

Allows developer to raise own error or customize error as shown below.

Syntax

Err.Raise(Number, Source, Description, HelpFile, HelpContext

Code example

Public Sub ErrorRaiseExample()
    Dim A As Integer
    Dim B As Integer
    A = 5
    B = 5
    
    'Check if A is equal to B
    If A = B Then
        Err.Raise Number:=123, Description:="A cannot be equal to B"
    End If
    
End Sub

Output

Err.Clear

Some times uses may require to continue execution exceptionally, the Clear method will allow user to clear or suppress the error.

Code example

Public Sub ClearErrorExample()
    On Error GoTo myError
    
    'code to be executed
    
'Define lable
myError:
'Define Error
If Err.Number <> 0 Then
    'Clear error
    Err.Clear
End If

Err.Number

Each error in VBA has a unique number to be identified. User can trap errors with the help of Error number and take necessary action as shown below where we try to perform division between Integer and String and Error Number 13 would be generated by compiler which is known for Type Mismatch.

Code example

Public Sub ErrorNumberExample()
    On Error GoTo myError
    
    Dim a As Integer
    Dim b As String
    a = 5
    b = "k"
    
    Debug.Print a / b
    
'Define lable
myError:
'Define Error
If Err.Number = 13 Then
    MsgBox "You are trying to perform operation between cross data types"
End If
End Sub

Output

There are various properties offered by Err object in VBA (Visual Basic for Applications) as listed below:

  • Description
  • HelpContext
  • HelpFile
  • LastDllError
  • Source

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