while filling data grid view using data reader application get hang

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VB

WinForms

DataGridView

I am working on windows form application
i have a form and data grid view..i am filling this data gridview in button click
in button click i am calling my function..my function like this:

Sub filldgv()
DGVReleased.Rows.Clear()
Dim carid As String
            Dim VehicleNo As String
            Dim DriverID As String
            Dim krrt As Integer
            Dim Dt As Integer
 Dim cmd As New SqlCommand("IBS_fetchresleaseVehicle", con.connect)
            cmd.CommandType = CommandType.StoredProcedure
            cmd.Parameters.Add("@locid", SqlDbType.Int).Value = Glocid
dr = cmd.ExecuteReader
            While dr.Read
                If dr("TBarcode") Is DBNull.Value Then
                    carid = ""
                Else
                    carid = dr("TBarcode")
                End If
                If dr("PlateNo") Is DBNull.Value Then
                    VehicleNo = ""
                Else
                    VehicleNo = dr("PlateNo")
                End If
                If dr("DelEcode") Is DBNull.Value Then
                    DriverID = ""
                Else
                    DriverID = dr("DelEcode")
                End If
                If dr("KRRT") Is DBNull.Value Then
                Else
                    krrt = dr("KRRT")
                End If
                If dr("DT") Is DBNull.Value Then
                Else
                    Dt = dr("DT")
                End If
                Dim row0 As String() = {carid, VehicleNo, DriverID, krrt, Dt}
                DGVReleased.Rows.Insert(0, row0)
            End While
            dr.Close()
            con.disconnect()
End Sub 

in button click event i am calling my function

Public Sub BtnRefresh_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnRefresh.Click
        filldgv()
        changecolor()
End Sub 

but when ever data is increasing the grid view my application is getting hanging(i mean if the data grid view loading around 100 s of record then application is hanging)
so in btnrefresh click i called background worker..but still my application is getting hanging