如何防止显示全部上机学生时重复

Private Sub showAll_Click()
    Dim txtsqlOn As String
    Dim msgtext As String
    Dim mrcOn As ADODB.Recordset
    Dim i As Integer
    Dim j As Integer
    txtsqlOn = "select * from online_info"
    Set mrcOn = executeSQL(txtsqlOn, msgtext)
    
    With myFlexGrid
        .CellAlignment = 4
        .Rows = 1
        .TextMatrix(0, 0) = "卡号"
        .TextMatrix(0, 1) = "姓名"
        .TextMatrix(0, 2) = "上机日期"
        .TextMatrix(0, 3) = "上机时间"
        .TextMatrix(0, 4) = "机房号"
        Do While Not mrcOn.EOF
            .CellAlignment = 4
            .Rows = .Rows + 1
            .TextMatrix(.Rows - 1, 0) = mrcOn!cardno
            .TextMatrix(.Rows - 1, 1) = mrcOn!studentname
            .TextMatrix(.Rows - 1, 2) = mrcOn!ondate
            .TextMatrix(.Rows - 1, 3) = mrcOn!OnTime
            .TextMatrix(.Rows - 1, 4) = mrcOn!computer
            mrcOn.MoveNext
            For i = 0 To .TextMatrix(.Rows - 1, 0)
          '  .Rows = .Rows + 1
                For j = j + 1 To Val(Trim(.TextMatrix(.Rows - 1, 0)))
                If .TextMatrix(i, 0) = .TextMatrix(j, 0) Then
                    .RemoveItem j
                    Exit Sub
                Else
                
                End If
            Next j
        Next i
        Loop
    End With
End Sub