为什么tableadaptor会停止执行代码块？

Question

    private void form_Load()
    {
        this.purchase_OrderTableAdapter.Fill(this.purchase_Order_DataSet.Purchase_Order);
        this.purchase_Order_ItemsTableAdapter.Fill(this.purchase_Order_DataSet.Purchase_Order_Items);
        this.inventoryTableAdapter.Fill(this.purchase_Order_DataSet.Inventory);

        part_NumberComboBox.SelectedValue = 0;
        order_QuantityTextBox.Text = "";
        part_DescriptionTextBox.Text = "";
        vendorTextBox.Text = "";

        part_NumberComboBox.Select();
    }

我已重建此表单两次以使其正常工作。现在它再次无法正常工作。执行inventoryTableAdapter时代码执行退出代码块，我无法找出原因。有什么想法吗？