工作流学习过程-自定义活动

例2：订单处理

顺序工作流如图：

 

后台代码：

public sealed partial class OrderWorkflow : SequentialWorkflowActivity
    {
        public OrderWorkflow()
        {
            InitializeComponent();
        }

        public int AccountId { get; set; }
        private double accountAmount;
        private bool accountExist;

        public int GoodsID { get; set; }
        private double goodsAmount;
        private bool goodsExist;

        private void AccountNull_ExecuteCode(object sender, EventArgs e)
        {
            Console.Write(" this is accountId : {0} is null ", AccountId.ToString());
        }

        private void CheckAccount_ExecuteCode(object sender, EventArgs e)
        {
            switch (AccountId)
            {
                case 1001:
                    accountAmount = 100;
                    accountExist = true;
                    break;
                case 1002:
                    accountAmount = 500;
                    accountExist = false;
                    break;
                case 1003:
                    accountAmount = 1000;
                    accountExist = true;
                    break;
                default:
                    accountAmount = 0;
                    accountExist = false;
                    break;
            }
        }

        private void CheckGoods_ExecuteCode(object sender, EventArgs e)
        {
            switch (GoodsID)
            {
                case 2001:
                    goodsAmount = 20;
                    goodsExist = true;
                    break;
                case 2002:
                    goodsAmount = 30;
                    goodsExist = false;
                    break;
                case 2003:
                    goodsAmount = 40;
                    goodsExist = true;
                    break;
                default:
                    goodsAmount = 0;
                    goodsExist = false;
                    break;
            }
        }

        private void GoodsNull_ExecuteCode(object sender, EventArgs e)
        {
            Console.Write(" this is goodsId : {0} is null ", GoodsID.ToString());
        }

        private void AmountNotEnough_ExecuteCode(object sender, EventArgs e)
        {
            Console.Write(" Sorry: your account's amount is {0},  this is goodsId's amount is {1} ", accountAmount.ToString(), goodsAmount.ToString());
        }

        private void CalOrder_ExecuteCode(object sender, EventArgs e)
        {
            this.accountAmount -= goodsAmount;
            Console.Write(" your order is success!! your account' amount is {0} ", this.accountAmount.ToString());
        }

我们清楚这里涉及到账号和产品的验证过程，如何整个系统中不可能仅仅在订单处理过程中附带该过程
因此我们应尽可能的细化这些步骤。这就是自定义活动
第一验证账号信息：AccountActivity 活动名称应以Activity结尾
代码如下：

public sealed partial class AccountActivity: Activity
    {
        public AccountActivity()
        {
            InitializeComponent();
        }

        public static DependencyProperty AccountIdProperty = DependencyProperty.Register("AccountId", typeof(int), typeof(AccountActivity));

        [DescriptionAttribute("AccountId")]
        [CategoryAttribute("AccountId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public int AccountId
        {
            get
            {
                return ((int)(base.GetValue(AccountActivity.AccountIdProperty)));
            }
            set
            {
                base.SetValue(AccountActivity.AccountIdProperty, value);
            }
        }

        public static DependencyProperty AccountAmountProperty = DependencyProperty.Register("AccountAmount", typeof(double), typeof(AccountActivity));

        [DescriptionAttribute("AccountAmount")]
        [CategoryAttribute("AccountAmount Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public double AccountAmount
        {
            get
            {
                return ((double)(base.GetValue(AccountActivity.AccountAmountProperty)));
            }
            set
            {
                base.SetValue(AccountActivity.AccountAmountProperty, value);
            }
        }
        public static DependencyProperty AccountExistProperty = DependencyProperty.Register("AccountExist", typeof(bool), typeof(AccountActivity));

        [DescriptionAttribute("AccountExist")]
        [CategoryAttribute("AccountExist Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public bool AccountExist
        {
            get
            {
                return ((bool)(base.GetValue(AccountActivity.AccountExistProperty)));
            }
            set
            {
                base.SetValue(AccountActivity.AccountExistProperty, value);
            }
        }


        protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
        {
            switch (AccountId)
            {
                case 1001:
                    AccountAmount = 100;
                    AccountExist = true;
                    break;
                case 1002:
                    AccountAmount = 505;
                    AccountExist = false;
                    break;
                default:
                    AccountAmount = 0;
                    AccountExist = false;
                    break;
            }
            Console.Write(" this accmountId is {0} exist is {1} ", AccountId.ToString(), AccountExist.ToString());
            return base.Execute(executionContext);
        }
    }

 第二产品信息验证 

public partial class GoodsActivity: Activity
    {
        public GoodsActivity()
        {
            InitializeComponent();
        }

        public static DependencyProperty GoodsIdProperty = DependencyProperty.Register("GoodsId", typeof(int), typeof(GoodsActivity));

        [DescriptionAttribute("GoodsId")]
        [CategoryAttribute("GoodsId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public int GoodsId
        {
            get
            {
                return ((int)(base.GetValue(GoodsActivity.GoodsIdProperty)));
            }
            set
            {
                base.SetValue(GoodsActivity.GoodsIdProperty, value);
            }
        }

        public static DependencyProperty GoodsAmountProperty = DependencyProperty.Register("GoodsAmount", typeof(double), typeof(GoodsActivity));

        [DescriptionAttribute("GoodsAmount")]
        [CategoryAttribute("GoodsAmount Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public double GoodsAmount
        {
            get
            {
                return ((double)(base.GetValue(GoodsActivity.GoodsAmountProperty)));
            }
            set
            {
                base.SetValue(GoodsActivity.GoodsAmountProperty, value);
            }
        }

        public static DependencyProperty GoodsExistProperty = DependencyProperty.Register("GoodsExist", typeof(bool), typeof(GoodsActivity));

        [DescriptionAttribute("GoodsExist")]
        [CategoryAttribute("GoodsExist Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public bool GoodsExist
        {
            get
            {
                return ((bool)(base.GetValue(GoodsActivity.GoodsExistProperty)));
            }
            set
            {
                base.SetValue(GoodsActivity.GoodsExistProperty, value);
            }
        }

        protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
        {
            switch (GoodsId)
            {
                case 2001:
                    GoodsAmount = 50;
                    GoodsExist = true;
                    break;
                case 2002:
                    GoodsAmount = 100;
                    GoodsExist = false;
                    break;
                default:
                    GoodsAmount = 0;
                    GoodsExist = false;                    
                    break;
            }
            Console.Write("this GoodsId is {0} exist is {1} ", GoodsId.ToString(), GoodsExist.ToString());
            return base.Execute(executionContext);
        }
    }

第三订单处理 

public sealed partial class OrderActivity : Activity
    {
        public OrderActivity()
        {
            InitializeComponent();
        }

        public static DependencyProperty AccountIdProperty = DependencyProperty.Register("AccountId", typeof(int), typeof(OrderActivity));

        [DescriptionAttribute("AccountId")]
        [CategoryAttribute("AccountId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public int AccountId
        {
            get
            {
                return ((int)(base.GetValue(OrderActivity.AccountIdProperty)));
            }
            set
            {
                base.SetValue(OrderActivity.AccountIdProperty, value);
            }
        }

        public static DependencyProperty GoodsIdProperty = DependencyProperty.Register("GoodsId", typeof(int), typeof(OrderActivity));

        [DescriptionAttribute("GoodsId")]
        [CategoryAttribute("GoodsId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public int GoodsId
        {
            get
            {
                return ((int)(base.GetValue(OrderActivity.GoodsIdProperty)));
            }
            set
            {
                base.SetValue(OrderActivity.GoodsIdProperty, value);
            }
        }

        protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
        {
            Console.Write("this AccountId is {0} ", AccountId.ToString());
            Console.Write("this GoodsId is {0} ", GoodsId.ToString());
            return base.Execute(executionContext);
        }
    }

 自定义活动到现在就都已经完成了。
来看看新工作流是什么样吧
新建顺序工作流
CustomerOrderActivity

两个工作流的任务是相同的。后者别前者更容易进行理解与维护，而产生的附加活动也能为其他工作流重用
需要指出的是 工作流的的各个活动的 属性可以互相绑定，而达到传递的目的
点击活动的属性。选择AccountID属性后点击后面的...弹出页面如图：

后台代码：

public sealed partial class CustomerOrderActivity : SequentialWorkflowActivity
    {
        public CustomerOrderActivity()
        {
            InitializeComponent();
        }
        public static DependencyProperty AccountIdProperty = DependencyProperty.Register("AccountId", typeof(int), typeof(CustomerOrderActivity));

        [DescriptionAttribute("AccountId")]
        [CategoryAttribute("AccountId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public int AccountId
        {
            get
            {
                return ((int)(base.GetValue(CustomerOrderActivity.AccountIdProperty)));
            }
            set
            {
                base.SetValue(CustomerOrderActivity.AccountIdProperty, value);
            }
        }

        public static DependencyProperty GoodsIdProperty = DependencyProperty.Register("GoodsId", typeof(int), typeof(CustomerOrderActivity));

        [DescriptionAttribute("GoodsId")]
        [CategoryAttribute("GoodsId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public int GoodsId
        {
            get
            {
                return ((int)(base.GetValue(CustomerOrderActivity.GoodsIdProperty)));
            }
            set
            {
                base.SetValue(CustomerOrderActivity.GoodsIdProperty, value);
            }
        }

 可以看出 工作流里 的代码很少了。更清爽了。因为主要的工作都已经在自定义活动中完成了。。。