文字列が見つかるまでファイルの先頭でファイルを検索するコードを書いています。
動作するコードは次のとおりです。
Private Function ReadTextFileUpto(ByVal txtFile As String, ByVal searchString As String) As String
Dim result As String = String.Empty
Dim sb As New System.Text.StringBuilder()
Dim previousLength As Integer = 0
Using reader As New IO.StreamReader(txtFile)
'Read the file 1 char at a time and append it to sb
While reader.Peek >= 0
sb.Append(Convert.ToChar(reader.Read))
'store the current length of sb
previousLength = sb.Length
'attemp to replace the search string with an empty string. If the length changed after the replacement
'then the following conditions must be true:
' 1. we have found the search string in sb.
' 2. the search string was at the end of sb.
sb.Replace(searchString, String.Empty)
If sb.Length < previousLength Then
'since we have found the search string, exit the loop and return the string currently in sb.
result = sb.ToString()
Exit While
End If
End While
End Using
Return result
End Function
ファイル内の開始位置を選択して検索を開始できるように、このコードを編集したいと思います。
これが私が取り組んでいるコードです：
Public Function ReadTextFileUpto(ByVal txtFile As String, ByVal searchString As String, integerStartPosition As Integer) As String
Dim result As String = String.Empty
Dim sb As New System.Text.StringBuilder()
Dim previousLength As Integer = 0
Using reader As New IO.StreamReader(txtFile)
'Read the file 1 char at a time and append it to sb
While reader.Peek >= integerStartPosition
sb.Append(Convert.ToChar(reader.Read))
'store the current length of sb
previousLength = sb.Length
'attemp to replace the search string with an empty string. If the length changed after the replacement
'then the following conditions must be true:
' 1. we have found the search string in sb.
' 2. the search string was at the end of sb.
sb.Replace(searchString, String.Empty)
If sb.Length < previousLength Then
'since we have found the search string, exit the loop and return the string currently in sb.
result = sb.ToString()
Exit While
End If
End While
End Using
Return result
End Function
これを機能させるために助けてもらえますか？
最終コード
Public Function ReadTextFileUpto(ByVal txtFile As String, ByVal searchString As String, integerStartPosition As Integer) As String
Dim result As String = String.Empty
Dim sb As New System.Text.StringBuilder()
Dim tmpString As String = ""
Dim previousLength As Integer = -1
Dim integerCurrentPosition As Integer
Using reader As New IO.StreamReader(txtFile)
While reader.Peek >= 0
integerCurrentPosition += 1
tmpString = Convert.ToChar(reader.Read)
If integerCurrentPosition > integerStartPosition Then
sb.Append(tmpString)
previousLength = sb.Length
sb.Replace(searchString, String.Empty)
If sb.Length < previousLength Then
result = sb.ToString()
Exit While
End If
End If
End While
End Using
Return result
End Function