[02/03] dropDownList.SelectedIndexChanged

i've written following code but the problem is it doesnot change the value "txtModelCode" everytime; another value is selected from the dropdown list

VB Code:

Private
 
Sub dropModels_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles dropModels.SelectedIndexChanged 
 
Dim objEquipment As BusinessLogicLayer.Equipments = Equipments.GetModelCode(dropModels.SelectedItem.Value) 
txtModelCode.Text = objEquipment.ModelCode
 
 
End Sub

while the values are loaded during page load

VB Code:

Private
 
Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
If
 
Not Page.IsPostBack Then 
dropModels.DataSource = Equipments.GetAllModels
 
dropModels.DataTextField = "Model"
 
dropModels.DataBind()
 
Dim
 
objEquipment As BusinessLogicLayer.Equipments = Equipments.GetModelCode(dropModels.SelectedItem.Value) 
txtModelCode.Text = objEquipment.ModelCode
 
End
 
If 
 
End Sub