vb.net问题 如何读取一个txt文件的内容并判断

Imports System.IO

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim r As New StreamReader("C:\jq.TXT") '打开文件

Dim Mytxt As String = ""

Dim s As String

Do While r.Peek >-1 '是否到文件升早败晌尾

s = r.ReadLine '从打开的吵枯雀文件中读取一行内容

Mytxt = Mytxt &s &vbCrLf '逐行读取文本，并连接到变量Mytxt中

Loop

r.Close() '关闭对象

'判断是否与变量相等etjq，略了吧？？？

End Sub

End Class

整汪改体思路如下：

lineinput 读出到字符然后判断是否为空。

可以用Len(*)=0判断，也可以用Trim(*)=""判断，或者Len(Trim(*))=0也可。

参考代码如下：

Public Function RedTextFile(Filename As String) As String

Dim FileID As Long

Dim InputStr As String

Dim LineStr As String

DIM I AS LONG

On Error Resume Next

InputStr = "": LineStr = ""盯渣

FileID = FreeFile()

Open Filename For Input As #FileID

Do While Not EOF(FileID) ' 循环至文困则判件尾。

I=I+1

LineStr = ""

Line Input #FileID, LineStr

IF LEN(TRIM$(LINESTR))=0 THEN

DEBUG.PRINT I &"是空行"

END IF

'InputStr = InputStr &LineStr

Loop

Close #FileID

RedTextFile = IIf(Err.Number = 0, InputStr, "")

Err.Clear

End Function

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