求一个VB。NET的算法，高分相送！在线急等！

[zhangye820911]

TextBox中，输入日期类型，可以有以下几种方法
yyyy/mm
yyyy/m
yy/mm
yy/m
yyyymm
yymm
在进入数据库前，全部转换成yyyy/mm格式！

[dragonlus]

try
{
datetime a = datetime.parse(textbox1.text.trim());
string sTime = a.toString("yyyy/MM");
}catch(Exception e1)
{
messagebox.show("格式錯誤!");
}

[阿Deee]

占上先

[zhangye820911]

dragonlus(毒龙)
我要的是VB。NET的，麻烦了啊

[syeerzy]

数据库里是varchar？

[syeerzy]

Try
Dim a As datetime = datetime.parse(textbox1.text.trim)
Dim sTime As String = a.toString("yyyy/MM")
Catch e1 As Exception
messagebox.show("格式錯誤!")
End Try

[DengXingJie]

yyyy/mm
yyyy/m
yy/mm
yy/m
yyyymm
yymm
可能要对这种几种类型数据做出判断才行
也可以先把没"/"的加上"/"再做统一做转换

[vinsonhwj]

刚写出来的，给D意见。
Private Function DateFormat(ByVal str As String) As String
Dim sYear As String
Dim sMon As String
Dim i As Int32 = Strings.InStr(str, "/")

Select Case str.Length
Case 7
'yyyy/mm
If i > 0 Then
If Strings.Left(str, i - 1).Trim.Length = 4 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 2 Then
sMon = Strings.Mid(str, i + 1)
End If
End If
End If
Case 6
'yyyy/m
If i > 0 Then
If Strings.Left(str, i - 1).Trim.Length = 4 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 1 Then
sMon = Strings.Mid(str, i + 1).PadLeft(2, "0")
End If
End If
End If
'yyyymm
If i = 0 Then
sYear = Strings.Left(str, 4).Trim
sMon = Strings.Right(str, 2)
End If
Case 5
'yy/mm
If i > 0 Then
If Strings.Left(str, i - 1).Trim.Length = 2 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 2 Then
sMon = Strings.Mid(str, i + 1).PadLeft(2, "0")
End If
End If
End If
Case 4
'yy/m
If i > 0 Then
If Strings.Left(str, i - 1).Trim.Length = 2 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 1 Then
sMon = Strings.Mid(str, i + 1).PadLeft(2, "0")
Else
Throw New Exception("格式错误！")
End If
Else
Throw New Exception("格式错误！")
End If
End If

'yymm
If i = 0 Then
If Strings.Left(str, 2).Trim.Length = 2 Then
sYear = Strings.Left(str, 2).Trim
If Strings.Right(str, 2).Trim.Length = 2 Then
sMon = Strings.Right(str, 2).PadLeft(2, "0")
Else
Throw New Exception("格式错误！")
End If
Else
Throw New Exception("格式错误！")
End If
End If
End Select

If sYear.Trim.Length = 2 Then
sYear = Strings.Left(Now.Year, 2) & sYear
End If

Return sYear & "/" & sMon
End Function

[vinsonhwj]

有些地方漏加：Throw New Exception("格式错误！")，楼主补一下吧。

[vinsonhwj]

我又重新整理了一下。
--------------------------------------------------------------------------
Private Function DateFormat(ByVal str As String) As String
Dim sYear As String
Dim sMon As String
Dim ErrMsg As String = "日期格式错误!"
Dim i As Int32 = Strings.InStr(str, "/")

Select Case str.Length
Case 7
'yyyy/mm
If i > 0 Then
If Strings.Left(str, i - 1).Trim.Length = 4 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 2 Then
sMon = Strings.Mid(str, i + 1)
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If

Case 6
'yyyy/m
If i <> 0 Then
If Strings.Left(str, i - 1).Trim.Length = 4 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 1 Then
sMon = Strings.Mid(str, i + 1).PadLeft(2, "0")
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If
Else
'yyyymm
sYear = Strings.Left(str, 4).Trim
sMon = Strings.Right(str, 2)
End If

Case 5
'yy/mm
If i > 0 Then
If Strings.Left(str, i - 1).Trim.Length = 2 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 2 Then
sMon = Strings.Mid(str, i + 1).PadLeft(2, "0")
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If

Case 4
'yy/m
If i <> 0 Then
If Strings.Left(str, i - 1).Trim.Length = 2 Then
sYear = Strings.Left(str, i - 1).Trim
If Strings.Mid(str, i + 1).Trim.Length = 1 Then
sMon = Strings.Mid(str, i + 1).PadLeft(2, "0")
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If
Else
'yymm
If Strings.Left(str, 2).Trim.Length = 2 Then
sYear = Strings.Left(str, 2).Trim
If Strings.Right(str, 2).Trim.Length = 2 Then
sMon = Strings.Right(str, 2).PadLeft(2, "0")
Else
Throw New Exception(ErrMsg)
End If
Else
Throw New Exception(ErrMsg)
End If
End If
Case Else
Throw New Exception(ErrMsg)
End Select

If sYear.Trim.Length = 2 Then
sYear = Strings.Left(Now.Year, 2) & sYear
End If

Return sYear & "/" & sMon
End Function

[hertcloud]

Try
Dim tm As datetime = datetime.parse(textbox1.text.trim)
Dim sTime As String = tm.toString("yyyy/MM")
Catch ex1 As Exception
messagebox.show("格式錯誤!")
End Try

[startstartsvip]

可以放三个 textbox

看他还辖输入

[懒牛科技]

Try
Dim tm As datetime = datetime.parse(textbox1.text.trim)
Dim sTime As String = tm.toString("yyyy/MM")
Catch ex1 As Exception
messagebox.show("格式錯誤!")
End Try

[s_liangchao1s]

呵呵 来晚了 已经有答案了！！

[zhangye820911]

vinsonhwj()
我刚到公司，等会试下，一会就给你分

[zhangye820911]

vinsonhwj() 谢谢，绝对正解！