Visual Basic.NET - datagrid

tengo un problema con datagrid,que cada vez que ejecuto el programa,me trae de la base de datos,lo solicitado,mas las tablas en el datagrid me salen estaticas y no me permiten seleccionar una fila.¿que hacer en este caso?
Estoy adjuntando parte del codigo.

Private Sub RadioButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton1.Click
Dim consulta As Data.SqlClient.SqlDataAdapter
Dim wilson As String
Dim conection As Data.SqlClient.SqlConnection
Dim dataset As New DataSet("inventario")
Dim datatable As DataTable
wilson = "select titulo from inventario"
stringconeccion = "data source = ADESISENA6; initial catalog = sib_2;" & _
"integrated security=SSPI;persist security info=True; "
conection = New Data.SqlClient.SqlConnection(stringconeccion)
consulta = New Data.SqlClient.SqlDataAdapter(wilson, conection)
cbtipo_mat.Items.Clear()
consulta.Fill(dataset, "inventario")
datatable = dataset.Tables("inventario")
Dim a, i As Integer
a = datatable.Rows.Count()
cbtipo_mat.Items.Clear()
txt1.DataBindings.Clear()
txt1.DataBindings.Add("text", datatable, "titulo")
For i = 0 To a - 1
Me.BindingContext(datatable).Position = i
cbtipo_mat.Items.Insert(i, txt1.Text)
Next
End Sub
Private Sub RadioButton2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton2.Click
Dim consulta As Data.SqlClient.SqlDataAdapter
Dim wilson As String
Dim conection As Data.SqlClient.SqlConnection
Dim dataset As New DataSet("autores")
Dim datatable As DataTable
wilson = "select nom_autor,apellido_autor from autores"
stringconeccion = "data source = ADESISENA6; initial catalog = sib_2;" & _
"integrated security=SSPI;persist security info=True; "
conection = New Data.SqlClient.SqlConnection(stringconeccion)
consulta = New Data.SqlClient.SqlDataAdapter(wilson, conection)
cbtipo_mat.Items.Clear()
consulta.Fill(dataset, "autores")
datatable = dataset.Tables("autores")
Dim a, i As Integer
a = datatable.Rows.Count()
cbtipo_mat.Items.Clear()
txt1.DataBindings.Clear()
txt1.DataBindings.Add("text", datatable, "nom_autor")
For i = 0 To a - 1
Me.BindingContext(datatable).Position = i
cbtipo_mat.Items.Insert(i, txt1.Text)
Next
End Sub
Private Sub RadioButton3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton3.Click
Dim consulta As Data.SqlClient.SqlDataAdapter
Dim wilson As String
Dim conection As Data.SqlClient.SqlConnection
Dim dataset As New DataSet("temas")
Dim datatable As DataTable
wilson = "select temas from temas"
stringconeccion = "data source = ADESISENA6; initial catalog = sib_2;" & _
"integrated security=SSPI;persist security info=True; "
conection = New Data.SqlClient.SqlConnection(stringconeccion)
consulta = New Data.SqlClient.SqlDataAdapter(wilson, conection)
cbtipo_mat.Items.Clear()
consulta.Fill(dataset, "temas")
datatable = dataset.Tables("temas")
Dim a, i As Integer
a = datatable.Rows.Count()
txt1.DataBindings.Clear()
txt1.DataBindings.Add("text", datatable, "temas")
For i = 0 To a - 1
Me.BindingContext(datatable).Position = i
cbtipo_mat.Items.Insert(i, txt1.Text)
Next
End Sub
Private Sub Btnbuscar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btnbuscar.Click
If RadioButton1.Checked = True Then
Dim cnSQL As SqlConnection
Dim dtadapter As SqlDataAdapter
Dim ds As DataSet = New DataSet
Dim ti As String
ti = "select inventario.titulo,autores.nom_autor,autores.apellido_autor,inventario.estado from inventario inner join autores on inventario.num_invent= autores.num_invent where inventario.titulo = " & finv.alex(cbtipo_mat.SelectedItem)
Try
'asigno la coneccion al objeto coneccion
cnSQL = New SqlConnection(stringconeccion)
' Abrir coneccion
cnSQL.Open()
'hacer la consulta con dataadapter
dtadapter = New SqlDataAdapter(ti, cnSQL)
'poblar el dataset con la tabla que se quiere trabajar
dtadapter.Fill(ds, "inventario")
dtadapter.Fill(ds, "autores")
'cerrar coneccion
cnSQL.Close()
'crear un datagrid
Dim drColumna As DataGrid
'poblar el dataset con las tablas que se quieren trabajar
'dtadapter.Fill(ds)
dg.DataSource = ds
' dg.DataMember = "inventario"
'cerrar coneccion
cnSQL.Close()
'crear un datagrid
'Dim drcolumnas As DataGrid
Catch ex As Exception
MsgBox(ex.Message)
End Try
End If
If RadioButton2.Checked = True Then
Dim cnSQL As SqlConnection
Dim dtadapter As SqlDataAdapter
Dim ds As DataSet = New DataSet
Dim sa As String
sa = "select autores.nom_autor,autores.apellido_autor, inventario.titulo,inventario.num_invent,inventario.estado from autores inner join inventario on autores.num_invent=inventario.num_invent where autores.nom_autor=" & finv.alex(cbtipo_mat.SelectedItem)
Try
'asigno la coneccion al objeto coneccion
cnSQL = New SqlConnection(stringconeccion)
' Abrir coneccion
cnSQL.Open()
'hacer la consulta con dataadapter
dtadapter = New SqlDataAdapter(sa, cnSQL)
'poblar el dataset con la tabla que se quiere trabajar
dtadapter.Fill(ds, "autores")
'cerrar coneccion
cnSQL.Close()
'crear un datagrid
Dim drColumna As DataGrid
'poblar el dataset con las tablas que se quieren trabajar
dtadapter.Fill(ds)
dg.DataSource = ds
dg.DataMember = "autores"
'cerrar coneccion
cnSQL.Close()
'crear un datagrid
Dim drcolumnas As DataGrid
Catch ex As Exception
MsgBox(ex.Message)
End Try
End If
If RadioButton3.Checked = True Then
Dim cnSQL As SqlConnection
Dim dtadapter As SqlDataAdapter
Dim ds As DataSet = New DataSet
Dim te As String
te = "select temas.temas, inventario.titulo,inventario.num_invent,inventario.estado from inventario inner join temas on inventario.num_invent= temas.num_invent where temas.temas = " & finv.alex(cbtipo_mat.SelectedItem)

Try
'asigno la coneccion al objeto coneccion
cnSQL = New SqlConnection(stringconeccion)
' Abrir coneccion
cnSQL.Open()
'hacer la consulta con dataadapter
dtadapter = New SqlDataAdapter(te, cnSQL)
'poblar el dataset con la tabla que se quiere trabajar
dtadapter.Fill(ds, "inventario")
'cerrar coneccion
cnSQL.Close()
'crear un datagrid
Dim drColumna As DataGrid
'poblar el dataset con las tablas que se quieren trabajar
dtadapter.Fill(ds)
dg.DataSource = ds
dg.DataMember = "inventario"
'cerrar coneccion
cnSQL.Close()
'crear un datagrid
'Dim drcolumnas As DataGrid
Catch ex As Exception
MsgBox(ex.Message)
End Try
End If
End Sub
esperando respuestas.