C#'taki Barkod İşlemleri İçin Null Kontrolü Nasıl Yapılır

Imports IronBarCode

' BarcodeReader.Read() returns a BarcodeResults collection, not a single result
Dim results As BarcodeResults = BarcodeReader.Read("shipping-label.png")

' Null check: image was not recognized as a valid image source
' Empty check: image was valid but contained no detectable barcodes
If results Is Nothing OrElse results.Count = 0 Then
    ' Log, return a default, or throw a domain-specific exception
    Console.WriteLine("No barcodes found in the input image.")
    Return
End If

' Collection is safe to iterate; each BarcodeResult holds one decoded barcode
For Each result As BarcodeResult In results
    ' Guard individual result properties; partial scans or severely
    ' damaged barcodes can produce results where .Value is empty or whitespace
    If String.IsNullOrWhiteSpace(result.Value) Then
        Console.WriteLine($"Empty value detected for {result.BarcodeType}")
        Continue For
    End If

    ' BarcodeType identifies the symbology (Code128, QRCode, EAN8, etc.)
    Console.WriteLine($"Type: {result.BarcodeType}, Value: {result.Value}")
Next

Imports IronBarCode

' BarcodeReader.Read() returns a BarcodeResults collection, not a single result
Dim results As BarcodeResults = BarcodeReader.Read("shipping-label.png")

' Null check: image was not recognized as a valid image source
' Empty check: image was valid but contained no detectable barcodes
If results Is Nothing OrElse results.Count = 0 Then
    ' Log, return a default, or throw a domain-specific exception
    Console.WriteLine("No barcodes found in the input image.")
    Return
End If

' Collection is safe to iterate; each BarcodeResult holds one decoded barcode
For Each result As BarcodeResult In results
    ' Guard individual result properties; partial scans or severely
    ' damaged barcodes can produce results where .Value is empty or whitespace
    If String.IsNullOrWhiteSpace(result.Value) Then
        Console.WriteLine($"Empty value detected for {result.BarcodeType}")
        Continue For
    End If

    ' BarcodeType identifies the symbology (Code128, QRCode, EAN8, etc.)
    Console.WriteLine($"Type: {result.BarcodeType}, Value: {result.Value}")
Next

Imports IronBarCode

' ConfidenceThreshold filters low-quality reads before they enter the
' BarcodeResults collection. Reads below the threshold are discarded
' during scanning, not after, so no post-filtering of the collection is needed.
Dim options As New BarcodeReaderOptions With {
    .ConfidenceThreshold = 0.7  ' range 0.0 to 1.0; lower values accept weaker signals
}

Dim results As BarcodeResults = BarcodeReader.Read("shipping-label.png", options)

' Still check for null and empty even with a threshold applied;
' an image with no barcodes returns an empty collection, not null
If results Is Nothing OrElse results.Count = 0 Then
    Console.WriteLine("No barcodes met the confidence threshold.")
    Return
End If

For Each result In results
    Console.WriteLine($"Type: {result.BarcodeType}, Value: {result.Value}")
Next

Imports IronBarCode

' ConfidenceThreshold filters low-quality reads before they enter the
' BarcodeResults collection. Reads below the threshold are discarded
' during scanning, not after, so no post-filtering of the collection is needed.
Dim options As New BarcodeReaderOptions With {
    .ConfidenceThreshold = 0.7  ' range 0.0 to 1.0; lower values accept weaker signals
}

Dim results As BarcodeResults = BarcodeReader.Read("shipping-label.png", options)

' Still check for null and empty even with a threshold applied;
' an image with no barcodes returns an empty collection, not null
If results Is Nothing OrElse results.Count = 0 Then
    Console.WriteLine("No barcodes met the confidence threshold.")
    Return
End If

For Each result In results
    Console.WriteLine($"Type: {result.BarcodeType}, Value: {result.Value}")
Next

Imports IronBarCode

' Input may arrive from user input, a database, or an API response
Dim inputValue As String = GetValueFromUserOrDatabase() ' Could be Nothing

' Guard: null, empty, or whitespace input cannot produce a valid barcode
If String.IsNullOrWhiteSpace(inputValue) Then
    Console.WriteLine("Cannot generate barcode: input value is null or empty.")
    Return
End If

' Guard: format-specific constraints must be satisfied before encoding
' EAN-8 accepts exactly 7 or 8 numeric digits (the 8th is the check digit)
Dim encoding As BarcodeWriterEncoding = BarcodeWriterEncoding.EAN8
If encoding = BarcodeWriterEncoding.EAN8 AndAlso Not System.Text.RegularExpressions.Regex.IsMatch(inputValue, "^\d{7,8}$") Then
    Console.WriteLine("EAN-8 requires exactly 7 or 8 numeric digits.")
    Return
End If

' Input is validated; CreateBarcode will not throw for null or format mismatch
Dim barcode As GeneratedBarcode = BarcodeWriter.CreateBarcode(inputValue, encoding)
barcode.SaveAsPng("output-barcode.png")

Imports IronBarCode

' Input may arrive from user input, a database, or an API response
Dim inputValue As String = GetValueFromUserOrDatabase() ' Could be Nothing

' Guard: null, empty, or whitespace input cannot produce a valid barcode
If String.IsNullOrWhiteSpace(inputValue) Then
    Console.WriteLine("Cannot generate barcode: input value is null or empty.")
    Return
End If

' Guard: format-specific constraints must be satisfied before encoding
' EAN-8 accepts exactly 7 or 8 numeric digits (the 8th is the check digit)
Dim encoding As BarcodeWriterEncoding = BarcodeWriterEncoding.EAN8
If encoding = BarcodeWriterEncoding.EAN8 AndAlso Not System.Text.RegularExpressions.Regex.IsMatch(inputValue, "^\d{7,8}$") Then
    Console.WriteLine("EAN-8 requires exactly 7 or 8 numeric digits.")
    Return
End If

' Input is validated; CreateBarcode will not throw for null or format mismatch
Dim barcode As GeneratedBarcode = BarcodeWriter.CreateBarcode(inputValue, encoding)
barcode.SaveAsPng("output-barcode.png")

Imports IronBarCode
Imports System.Collections.Generic
Imports System.Linq

' Reusable validation helper — consolidates null, empty, value, and
' expected-format checks into a single method. Returns an empty list
' (never null) so callers do not need to null-check the return value.
Public Module BarcodeValidator
    Public Function GetValidResults(
        imagePath As String,
        Optional expectedType As BarcodeEncoding? = Nothing,
        Optional confidenceThreshold As Double = 0.7) As List(Of BarcodeResult)

        ' Apply confidence threshold at scan level via BarcodeReaderOptions
        Dim options As New BarcodeReaderOptions With {
            .ConfidenceThreshold = confidenceThreshold
        }

        Dim results As BarcodeResults = BarcodeReader.Read(imagePath, options)

        ' Return empty list instead of null so callers never need to null-check the return value
        If results Is Nothing OrElse results.Count = 0 Then
            Return New List(Of BarcodeResult)()
        End If

        Return results _
            .Where(Function(r) Not String.IsNullOrWhiteSpace(r.Value)) _          ' skip results with empty decoded data
            .Where(Function(r) expectedType Is Nothing OrElse r.BarcodeType = expectedType) _ ' null accepts any symbology
            .ToList()
    End Function
End Module

' Usage: pass the image path and the symbology you expect
Dim validated = BarcodeValidator.GetValidResults(
    "warehouse-scan.png",
    expectedType:=BarcodeEncoding.Code128,
    confidenceThreshold:=0.7)

If validated.Count = 0 Then
    ' No valid results; log the failure and skip downstream processing
    Return
End If

' All results have passed null, empty, type, and confidence checks
For Each barcode In validated
    SendToInventorySystem(barcode.Value, barcode.BarcodeType.ToString()) ' placeholder for your downstream call
Next barcode

Imports IronBarCode
Imports System.Collections.Generic
Imports System.Linq

' Reusable validation helper — consolidates null, empty, value, and
' expected-format checks into a single method. Returns an empty list
' (never null) so callers do not need to null-check the return value.
Public Module BarcodeValidator
    Public Function GetValidResults(
        imagePath As String,
        Optional expectedType As BarcodeEncoding? = Nothing,
        Optional confidenceThreshold As Double = 0.7) As List(Of BarcodeResult)

        ' Apply confidence threshold at scan level via BarcodeReaderOptions
        Dim options As New BarcodeReaderOptions With {
            .ConfidenceThreshold = confidenceThreshold
        }

        Dim results As BarcodeResults = BarcodeReader.Read(imagePath, options)

        ' Return empty list instead of null so callers never need to null-check the return value
        If results Is Nothing OrElse results.Count = 0 Then
            Return New List(Of BarcodeResult)()
        End If

        Return results _
            .Where(Function(r) Not String.IsNullOrWhiteSpace(r.Value)) _          ' skip results with empty decoded data
            .Where(Function(r) expectedType Is Nothing OrElse r.BarcodeType = expectedType) _ ' null accepts any symbology
            .ToList()
    End Function
End Module

' Usage: pass the image path and the symbology you expect
Dim validated = BarcodeValidator.GetValidResults(
    "warehouse-scan.png",
    expectedType:=BarcodeEncoding.Code128,
    confidenceThreshold:=0.7)

If validated.Count = 0 Then
    ' No valid results; log the failure and skip downstream processing
    Return
End If

' All results have passed null, empty, type, and confidence checks
For Each barcode In validated
    SendToInventorySystem(barcode.Value, barcode.BarcodeType.ToString()) ' placeholder for your downstream call
Next barcode