Question

我有一个DatagridView Checkboxcolumn我的目标是检查数据库中是否已存在Checked Row但我的代码没有提供我想要的输出。怎么了？

这是

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim conn As MySqlConnection = New MySqlConnection("datasource=localhost;database=operations;userid=root;password=admin1950;Convert Zero Datetime=True")
        conn.Open()
        Dim comm As MySqlCommand = New MySqlCommand()
        comm.Connection = conn
        Dim name As String
        For i As Integer = 0 To Me.DataGridView1.Rows.Count - 1 Step 1
            If Me.DataGridView1.Rows(i).Cells(0).Value = True Then
                name = Me.DataGridView1.Rows(i).Cells(1).Value
                comm.CommandText = "select ElecAssigned,ScheduleDate from assignments where ElecAssigned = '" & name & "' and ScheduleDate = @ScheduleDate"
                comm.Parameters.AddWithValue("@ScheduleDate", DateTimePicker1.Value)
                comm.ExecuteNonQuery()
                Dim reader As MySqlDataReader
                reader = comm.ExecuteReader
                If reader.HasRows Then
                    MsgBox("The persons that you Selected is also Scheduled Today.")
                End If
            End If
        Next
    End Sub

以下是情景。

我在表assignments中保存数据，看起来像这样。

以下是程序中的场景

我在Datagridview中检查了一行并在DateTimePicker中选择了一个与我的表格相同的日期，必须有一条消息，其中会显示The selected Person is also Scheduled Today

这是代码

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim connection As New MySqlConnection("datasource=localhost;database=operations;userid=root;password=admin1950;Convert Zero Datetime=True")
        Dim command As New MySqlCommand("SELECT COUNT(*) FROM Assignments WHERE ElecAssigned = @ElecAssigned AND ScheduleDate = @ScheduleDate", connection)
        Dim parameter = command.Parameters.Add("@ElecAssigned", MySqlDbType.VarChar, 50)

        command.Parameters.AddWithValue("@ScheduleDate", DateTimePicker1.Value)

        connection.Open()

        For Each row As DataGridViewRow In Me.DataGridView1.Rows
            If CBool(row.Cells(0).Value) Then
                parameter.Value = CStr(row.Cells(1).Value)

                If CInt(command.ExecuteScalar()) > 0 Then
                    'Match found.

                Else
                    MsgBox("The Personnel(s) you Selected is also Scheduled Today")
                    'No match found.
                    'Save It
                End If
            End If
        Next
    End Sub

无论选择多少，程序都会检查是否也检查了所选人员。

Answer 1

E.g。

Dim connection As New MySqlConnection("connection string here")
Dim command As New MySqlCommand("SELECT COUNT(*) FROM Assignments WHERE ElecAssigned = @ElecAssigned AND ScheduledDate = @ScheduledDate", connection)
Dim parameter = command.Parameters.Add("@ElecAssigned", MySqlDbType.VarChar, 50)

command.Parameters.AddWithValue("@ScheduledDate", DateTimePicker1.Value.Date) 'Add a word Date to check only the Date

connection.Open()

For Each row As DataGridViewRow In Me.DataGridView1.Rows
    If CBool(row.Cell(0).Value) Then
        parameter.Value = CStr(row.Cells(1).Value)

        If CInt(command.ExecuteScalar()) > 0 Then
            'Match found.
        Else
            'No match found.
        End If
    End If
Next

您可能需要进行一些小的调整，但如果您想单独了解每个选中的行，那么基本上就是这样做。

检查DataGridview中检查的行是否存在于数据库

1 个答案: