可以創建csv，但不能寫入它

Question

我的問題類似於這個post。我可以創建csv，但創建後無法寫入。但不像那篇文章，我沒有兩次創建文件。

我的代碼：

Dim path As String = "C:\xxx\yyy\" & csvFileName 

If File.Exists(path) = False Then 
    ' Create a file to write to. 
    Dim createText As String = String.Empty + Environment.NewLine 
    File.WriteAllText(path, createText) 
End If 


Dim sw As StreamWriter = New StreamWriter(csvFileName, True) 

'first, write all column names to csv. 
Dim sb As New StringBuilder 
For Each col As DataColumn In dt.Columns 
    sb.Append(col.ColumnName) 
Next 
sw.Write(sb.ToString) 

'now, write rows to csv. 
For Each row As DataRow In dt.Rows 
    sb = New StringBuilder 

    For Each col As DataColumn In dt.Columns 
     sb.Append(row(col.ColumnName)) 
    Next 

    sw.Write(sb.ToString) 
Next 

sw.Close() 

任何幫助表示讚賞。謝謝。

Answer 1

您在這裏使用兩個不同的文件名。該StreamWriter應該寫信給path而不是csvFileName：

Dim sw As StreamWriter = New StreamWriter(path, True) 

Answer 2

有很多問題在你的代碼

1. 你不寫列分隔符
2. 您正在使用的文件名，而不是完整的路徑
的
3. 您正在使用sw.Write()方法而不是sw.WriteLine()（所有文本將在一行上寫）

您可以使用下面的代碼：

Dim path As String = "C:\xxx\yyy\" & csvFileName 

    If File.Exists(path) = False Then 
    ' Create a file to write to. 
     Dim createText As String = String.Empty + Environment.NewLine 
     File.WriteAllText(path, createText) 
    End If 


    Using sw As StreamWriter = New StreamWriter(path, True) 

     'first, write all column names to csv. 
     Dim sb As New StringBuilder 

     For Each col As DataColumn In dt.Columns 
      sb.Append(col.ColumnName & ",") 
     Next 

     sw.WriteLine(sb.ToString) 

     'now, write rows to csv. 
     For Each row As DataRow In dt.Rows 
      sb = New StringBuilder 

      For Each col As DataColumn In dt.Columns 
       sb.Append(row(col.ColumnName).ToString & ",") 
      Next 

      sw.WriteLine(sb.ToString) 
     Next 

     sw.Close() 

    End Using