VB.Net 获取一个文件夹下多种格式的图片

Private Function GetImages(dirPath As String, ParamArray searchPatterns As String()) As String()
    If searchPatterns.Length <= 0 Then
        Return Nothing
    Else
        Dim di As New DirectoryInfo(dirPath)
        Dim fis As FileInfo()() = New FileInfo(searchPatterns.Length - 1)() {}
        Dim count As Integer = 0
        Dim i As Integer = 0
        While i < searchPatterns.Length
            Dim fileInfos As FileInfo() = di.GetFiles(searchPatterns(i))
            fis(i) = fileInfos
            count += fileInfos.Length
            System.Math.Max(System.Threading.Interlocked.Increment(i),i - 1)
        End While
        Dim files As String() = New String(count - 1) {}
        Dim n As Integer = 0
        Dim i As Integer = 0
        While i <= fis.GetUpperBound(0)
            Dim j As Integer = 0
            While j < fis(i).Length
                Dim temp As String = fis(i)(j).FullName
                files(n) = temp
                System.Math.Max(System.Threading.Interlocked.Increment(n),n - 1)
                System.Math.Max(System.Threading.Interlocked.Increment(j),j - 1)
            End While
            System.Math.Max(System.Threading.Interlocked.Increment(i),i - 1)
        End While
        Return files
    End If
End Function

Dim files As String() = GetPictures("*.gif", "*.jpg", "*.png")