public partial class AccountAdjustmentActivity: Activity
    {
        public AccountAdjustmentActivity()
        {
            InitializeComponent();
        }public static DependencyProperty AmountProperty = DependencyProperty.Register("Amount", typeof(decimal), typeof(AccountAdjustmentActivity));
        [DescriptionAttribute(
"Amount")]
        [CategoryAttribute("Amount Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public decimal Amount
        {
            get
            {
                return ((decimal)(base.GetValue(AccountAdjustmentActivity.AmountProperty)));
            }
            set
            {
                base.SetValue(AccountAdjustmentActivity.AmountProperty, value);
            }
        }public static DependencyProperty AccountIdProperty = DependencyProperty.Register("AccountId", typeof(string), typeof(AccountAdjustmentActivity));
        [DescriptionAttribute("AccountId")]
        [CategoryAttribute("AccountId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public string AccountId
        {
            get
            {
                return ((string)(base.GetValue(AccountAdjustmentActivity.AccountIdProperty)));
            }
            set
            {
                base.SetValue(AccountAdjustmentActivity.AccountIdProperty, value);
            }
        }public static DependencyProperty IsCreditProperty = DependencyProperty.Register("IsCredit", typeof(bool), typeof(AccountAdjustmentActivity));
        [DescriptionAttribute("IsCredit")]
        [CategoryAttribute("IsCredit Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public bool IsCredit
        {
            get
            {
                return ((bool)(base.GetValue(AccountAdjustmentActivity.IsCreditProperty)));
            }
            set
            {
                base.SetValue(AccountAdjustmentActivity.IsCreditProperty, value);
            }
        }protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
        {
            using ( SqlConnection connection = new SqlConnection(               
                    ConfigurationManager.ConnectionStrings
                    ["ProWorkflow"].ConnectionString))
            {
                connection.Open();
                if (!IsCredit)
                {
                    Decimal currentBal = GetCurrentBalance(connection, AccountId);
                    if (currentBal < Amount)
                    {
                        throw new ArgumentException("余额不足，无法处理");
                    }
                }
                UpdateBalance(connection, AccountId, Amount, IsCredit);
                connection.Close();
            }return base.Execute(executionContext);
        }private decimal GetCurrentBalance(SqlConnection connection, string accountId)
        {
            Decimal balance = 0;
            String sql = @"select balance from account where accountId = @AccountId";
            SqlCommand command = new SqlCommand(sql);
            SqlParameter p = new SqlParameter("@AccountId", accountId);
            command.Parameters.Add(p);
            command.Connection = connection;
            Object result = command.ExecuteScalar();
            if (result != null)
            {
                balance = (Decimal)result;
            }return balance;
        }private void UpdateBalance(SqlConnection connection, string accountId, decimal amount, bool isCredit)
        {
            String sql;
            if (isCredit)
            {
                sql =
                    @"update account set balance = balance + @Amount where accountId = @AccountId";
            }
            else
            {
                sql =
                    @"update account set balance = balance - @Amount where accountId = @AccountId";
            }
            SqlCommand command = new SqlCommand(sql);
            SqlParameter p = new SqlParameter("@AccountId", accountId);
            command.Parameters.Add(p);
            p = new SqlParameter("@Amount", amount);
            command.Parameters.Add(p);
            command.Connection = connection;
            command.ExecuteNonQuery();
        }
    }

public partial class AccountTransferWorkflow : SequentialWorkflowActivity
    {
        public AccountTransferWorkflow()
        {
            InitializeComponent();
        }public static DependencyProperty AmountProperty = DependencyProperty.Register("Amount", typeof(decimal), typeof(AccountTransferWorkflow));
        [DescriptionAttribute(
"Amount")]
        [CategoryAttribute("Amount Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public decimal Amount
        {
            get
            {
                return ((decimal)(base.GetValue(AccountTransferWorkflow.AmountProperty)));
            }
            set
            {
                base.SetValue(AccountTransferWorkflow.AmountProperty, value);
            }
        }public static DependencyProperty FromAccountIdProperty = DependencyProperty.Register("FromAccountId", typeof(string), typeof(AccountTransferWorkflow));
        [DescriptionAttribute("FromAccountId")]
        [CategoryAttribute("FromAccountId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public string FromAccountId
        {
            get
            {
                return ((string)(base.GetValue(AccountTransferWorkflow.FromAccountIdProperty)));
            }
            set
            {
                base.SetValue(AccountTransferWorkflow.FromAccountIdProperty, value);
            }
        }public static DependencyProperty ToAccountIdProperty = DependencyProperty.Register("ToAccountId", typeof(string), typeof(AccountTransferWorkflow));
        [DescriptionAttribute("ToAccountId")]
        [CategoryAttribute("ToAccountId Category")]
        [BrowsableAttribute(true)]
        [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
        public string ToAccountId
        {
            get
            {
                return ((string)(base.GetValue(AccountTransferWorkflow.ToAccountIdProperty)));
            }
            set
            {
                base.SetValue(AccountTransferWorkflow.ToAccountIdProperty, value);
            }
        }
    }

<connectionStrings>
    <add name="WorkflowPersistence" connectionString=
      "Integrated Security=SSPI;Initial Catalog=c6ps;
      Data Source=.;Integrated Security=SSPI" />
    <add name="ProWorkflow" connectionString="Integrated Security=SSPI;Initial Catalog=ProWorkflow;
      Data Source=.;Integrated Security=SSPI" />
  </connectionStrings>