Check if the row checked in DataGridview exist in database

Question

I have a DatagridView with a Checkboxcolumn My Goal here is to check if the Checked Row is already exist in the Database but my code does not give me the output I want. Whats wrong?

Here it is

 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

Here is the Scenario.

I save a Data in the Table assignments and it looks like this.

and here is the Scenario in the Program

I checked a row in the Datagridview and select a Date in DateTimePicker which is the same in the my table there must be Message that will show saying The selected Person is also Scheduled Today

here is the code

 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

Regardless of how many I select the program will check if the persons selected is also checked.

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

You might require a few small adjustments but that's basically the way to go about it if you want to know individually for each checked row.