Question

Imports System.Data.Sql
Imports System.Data.SqlClient

Public Class Main
    Dim c As New SqlCommand
    Dim connection As String = "Server=DESKTOP-7MC233A\SQLJOSE;database=AttendanceLog;user id=sa;password=pogi1234;"

    Private Sub Main_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Timer1.Enabled = True

        Dim dtmNow As DateTime = System.DateTime.Now

        If dtmNow.Hour > 0 And dtmNow.Hour < 11 Then
            Label2.Text = "Good morning"

        ElseIf dtmNow.Hour > 12 And dtmNow.Hour < 18 Then
            Label2.Text = "Good afternoon"

        ElseIf dtmNow.Hour > 19 And dtmNow.Hour < 23 Then
            Label2.Text = "Good evening "
        Else

        End If
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        lblDate.Text = Date.Now.ToString("MMM dd,yyyy")
        lblTime.Text = Date.Now.ToString("hh:mm:ss")
    End Sub

    Private Sub Label1_Click(sender As Object, e As EventArgs) Handles lblDate.Click

    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbNames.SelectedIndexChanged



    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Using con As New SqlConnection(connection)
            Try
                If con.State = ConnectionState.Closed Then
                    con.Open()
                End If

                With c
                    .Connection = con
                    .CommandText = "Insert into TimeIn values(@Name,@TimeIn,@Date)"
                    .CommandType = CommandType.Text

                    .Parameters.AddWithValue("@Name", cmbNames.Text)
                    .Parameters.AddWithValue("@TimeIn", lblTime.Text)
                    .Parameters.AddWithValue("@Date", lblDate.Text)

                    .ExecuteNonQuery()

                End With
                Dim dtmNow As DateTime = System.DateTime.Now

                If dtmNow.Hour > 9 Then
                    MsgBox("You are late!!!", MsgBoxStyle.Critical)
                ElseIf dtmNow.Hour < 9 Then

                    MsgBox("You are on time!", MsgBoxStyle.Information)

                End If



            Catch ex As Exception
                MsgBox("From: " & ex.Message)
            End Try
            con.Dispose()

        End Using

    End Sub
End Class

以下是我的代码，我很遗憾接下来要做的事情。在此先感谢您的帮助。

Answer 1

使用它后，每次使用sqlCommand 你可以使用：

Using c As New SqlCommand("commandtext", connection")

或者你可以......

With c
'after the execution
.Parameters.Clear()
.Dispose
End With

Answer 2

每次都创建一个新的sqlcommand。与每次创建新Connection的方式相同。

你遇到的问题是你在第二次传球时再次添加@name。

Using con As New SqlConnection(connection) 
    Using cmd as New SqlCommand(...)

    ....

    End Using
End Using

使用MS SQL作为我的数据库处理VB.net程序。当我试图在表格中插入另一个值时，会弹出此错误

2 个答案: