Vb.net Editing DatagridView - vb.net

Question

I created a simple program where I can search through a database table. Add data and remove data through a button. Now I want to be able to update the data within the datagrid view however i am getting the classic error: Dynamic SQL generation for the UpdateCommand is not supported against a SelectCommand that does not return any key column information.
I have the primary key in the data grid that is not attached to anything in the vb.net program nor in the database at this time. I am not sure what I am missing.
Public Class Form1
Dim cn As New SqlConnection("Data Source=;Initial Catalog=Inventory;User ID=;Password=")
Dim adap As New SqlDataAdapter("SELECT res_snbr, First_Name, Last_Name, Item FROM Inventory_Details", cn)
Dim builder As New SqlCommandBuilder(adap)
Dim dt As New DataTable
'Dim InventoryDetailsBindingSource As New BindingSource
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
DataGridView1.AllowUserToAddRows = True
DataGridView1.AllowUserToDeleteRows = True
DataGridView1.[ReadOnly] = False
adap.InsertCommand = builder.GetInsertCommand()
' adap.UpdateCommand = builder.GetUpdateCommand()
adap.UpdateCommand = builder.GetUpdateCommand
adap.Fill(dt)
InventoryDetailsBindingSource.DataSource = dt
DataGridView1.DataSource = InventoryDetailsBindingSource
End Sub
Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
If TextBox1.TextLength > 0 Then
InventoryDetailsBindingSource.Filter = String.Format("First_Name Like '%{0}%'", TextBox1.Text)
Else
InventoryDetailsBindingSource.Filter = String.Empty
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
adap.Update(dt)
MessageBox.Show("Saved successfully")
Catch ex As Exception
MessageBox.Show("Error updating database")
End Try
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
adap.Update(dt)
DataGridView1.[ReadOnly] = True
Button2.Enabled = False
End Sub
End Class

Answer 1

Actually I was incorrect. I did not have a primary key set on my database. I dropped my table - recreated with primary key.