Question

如果未传递参数变量，则此代码抛出“从字符串转换”“到”类型'日期'无效的异常。“

这是我的代码。

 Public Shared ReadOnly Property Request_projectStartDate() As Date
        Get
            Dim _value As String = Nothing

            If Not HttpContext.Current.Request.QueryString("projectStartDate") Is Nothing Then
                _value = HttpContext.Current.Request.QueryString("projectStartDate").ToString()
            End If

            Return CDate(_value)
        End Get
    End Property

Answer 1

您可以查看@Massimiliano报告的内容以及另外一项检查

If Request.QueryString.HasKeys() Then

   // Check for specified querystrings...
   If Not String.IsNullOrEmpty(Request.QueryString("projectStartDate")) Then
       // Your logic
   End If

End If

Answer 2

If Not String.IsNullOrEmpty(Request.QueryString("projectStartDate")) Then
    //
End If

Answer 3

如果Request.QueryString（＆＃34; projectStartDate＆＃34;）IsNot Nothing和Request.QueryString（＆＃34; projectStartDate＆＃34;）＆lt;＆gt; ＆＃34;＆＃34;然后

如果未传递参数，如何避免vb.net中的请求查询字符串异常

3 个答案: