vb.net - 从字符串转换日期和/或时间时转换失败

Question

sql = "insert into tbl_nurse(nurseid,nursename,deptname,dob,doj,qualification,salary)"
            sql = sql & "values('" & txtNurseid.Text & "','" & TxtNursename.Text & "','" & Cmbdept.Text & "',convert(date,'" & DateTimePicker1.Value & "',103),convert(date,'" & DateTimePicker2.Value & "',103),'" & Txtqualification.Text & "','" & txtsalary.Text & "')"
            conn.Execute(sql)

Answer 1

您应该使用sql-parameters来避免sql-injection并防止出现此类转换问题。

假设 SQL-Server 的示例：

Const sql = "INSERT INTO tbl_nurse(nurseid,nursename,deptname,dob,doj,qualification,salary)" & vbCrLf & _
            "VALUES(@nurseid, @nursename, @deptname, @dob, @doj, @qualification, @salary)"
Using con = New SqlConnection("Insert Your Connection String Here")
    Using cmd = New SqlCommand(sql, con)
        cmd.Parameters.AddWithValue("@nurseid", txtNurseid.Text)
        cmd.Parameters.AddWithValue("@nursename", TxtNursename.Text)
        cmd.Parameters.AddWithValue("@deptname", Cmbdept.Text)
        ' -- No conversion problems anymore because you pass a DateTime -- '
        cmd.Parameters.AddWithValue("@dob", DateTimePicker1.Value)
        ' ... other parameters ... '
        con.Open()
        Dim affectedRecords As Int32 = cmd.ExecuteNonQuery()
    End Using
End Using

Answer 2

试着这样改变..

sql = "insert into tbl_nurse(nurseid,nursename,deptname,dob,doj,qualification,salary)"

sql = sql & " values('" & txtNurseid.Text & "','" & TxtNursename.Text & "','" & Cmbdept.Text & "',#" & format(DateTimePicker1.Value.Date) & "#,#" & format(DateTimePicker2.Value.Date) & "#,'" & Txtqualification.Text & "','" & txtsalary.Text & "')"

conn.Execute(sql)

正如 Tim Scmelter 所说..你最好使用参数化输入

Answer 3

如下添加参数，它就像魅力一样

cmnd.Parameters.Add("@date_time", SqlDbType.DateTime).Value = datetime.Date;

原帖在这里：

https://www.codeproject.com/Answers/552202/Conversionplusfailedpluswhenplusconvertingplusdate#answer3