bindingNavigator1 里的ComboBox无法更改

private void Form1_Load(object sender, EventArgs e)
{

bind();

txtPriorty.DataBindings.Clear();
txtPriorty.DataBindings.Add("text", bindingSource1, "Priorty");
comValid.DataBindings.Clear();
comValid.DataBindings.Add("SelectedValue", bindingSource1, "Valid");
comwtID.DataBindings.Clear();
comwtID.DataBindings.Add("SelectedValue", bindingSource1, "wtID");

comwtID.DataSource = new BLL.Warehouse().getWarehouseType();
comwtID.DisplayMember = "TypeName";
comwtID.ValueMember = "wtID";
comValid.DataSource = new BLL.Valids().getValid();
comValid.DisplayMember = "ValidName";
comValid.ValueMember = "Valid";

}

private void bind()
{

bindingSource1.DataSource = new BLL.Warehouse().getWarehouse();
bindingNavigator1.BindingSource = bindingSource1;
dataGridView1.DataSource = bindingSource1;

}

ComboBox 运行是没错的，但是，想改comValid和comwtID里的值就没法改，因为，只在离开这comValid和comwtID这两个就改回原来的数据

[解决办法]
编程思想不对。

既然知道问题症结所在，就应该能解决。