Mediar.Framework—业务的实现2(UI 与对象实体的通信)

   UI 与对象实体的通信

1 前面已经谈到UI通过对象属性的名称从对象中获取值，UI控件的值是在changed 事件后赋给对象。因为对象实体是已知的，UI控件的值对应的是对象的属性，所以根据对象中属性名称获取值是比较容易的。当然设置对象与获取对象的值，都在对象实体中有相应的方法。这个方法比较通用，现在有不少架构都这么写.下面两个方法都使用了反射对property进行读写.

 

 public object GetValue(string propertyName)

        {

            Type t;

            System.Reflection.PropertyInfo p;

            System.Reflection.MethodInfo m;

            object rtn;

            if ((propertyName == "UniqueID"))

            {

                return mUniqueID;

            }

            string nestedPropertyName = string.Empty;

            bool nestedProperty = false;

            int dotIndex;

            dotIndex = propertyName.IndexOf('.');

            if ((dotIndex > -1))

            {

                nestedPropertyName = propertyName.Substring(dotIndex + 1);

                propertyName = propertyName.Substring(0, dotIndex);

                nestedProperty = true;

            }

            t = this.GetType();

            p = t.GetProperty(propertyName);

            if (p != null)

            {

                m = p.GetGetMethod(false);

                if ((m == null))

                {

                    throw new Exception("Property: " + t.Name + "." + propertyName + " has no GET method.");

                }

            }

            else

            {

                m = t.GetMethod(propertyName);

                if ((m == null))

                {

                    throw new Exception("Function: " + t.Name + "." + propertyName + " does not exist.");

                }

            }

            rtn = m.Invoke(this, null);

            if ((!((rtn == null)) && nestedProperty))

            {

                rtn = ((BizObject)(rtn)).GetValue(nestedPropertyName);

            }

            return rtn;

        }

 

        public void SetProperty(string propertyName, object value)

        {

            try

            {

                Type t;

                System.Reflection.PropertyInfo p;

                System.Reflection.MethodInfo m;

                string nestedPropertyName = string.Empty;

                bool nestedProperty = false;

                int dotIndex;

                System.Exception Ex;

                t = this.GetType();

                dotIndex = propertyName.IndexOf('.');

                if ((dotIndex > -1))

                {

                    nestedPropertyName = propertyName.Substring(dotIndex + 1);

                    propertyName = propertyName.Substring(0, dotIndex);

                    nestedProperty = true;

                }

                p = t.GetProperty(propertyName);

                if ((p == null))

                {

                    Ex = new CustomBizObjectException("Property: " + t.Name + "." + propertyName + " does not exist.");

                    Ex.Source = "BizObject_SetProperty(propertyName, value)";

                    throw Ex;

                }

                else

                {

                    if (nestedProperty)

                    {

                        object rtn;

                        rtn = this.GetValue(propertyName);

                        if ((rtn == null))

                        {

                            Ex = new CustomBizObjectException(t.Name + "." + propertyName + " does not exist.");

                            Ex.Source = "BizObject_SetProperty(propertyName, value)";

                            throw Ex;

                        }

                        else

                        {

                            ((BizObject)(rtn)).SetProperty(nestedPropertyName, value);

                        }

                   }

                    else

                    {

                        m = p.GetSetMethod(false);

                        if ((m == null))

                        {

                            Ex = new CustomBizObjectException("Function: " + t.Name + "." + propertyName + " has no SET method.");

                            Ex.Source = "BizObject_SetProperty(propertyName, value)";

                            throw Ex;

                        }

                        else

                        {

                            if ((value == null))

                            {

                                m.Invoke(this, new object[] { null });

                            }

                            else if ((value.GetType().IsSubclassOf(p.PropertyType)))

                            {

                                m.Invoke(this, new object[] { value });

                            }

                            else

                            {

                                m.Invoke(this, new object[] { System.Convert.ChangeType(value, p.PropertyType) });

                            }

                        }

                    }

                }

            }

            catch (Exception ex)

            {

                ex = new CustomBizObjectException("Caught Exception when Setting " + this.GetType().Name + "." + propertyName, ex);

                ex.Source = "BizObject_SetProperty(propertyName, value)";

                throw ex;

            }

           

        }

2 新建，保存，刷新，取消

     在主窗口中应该可以看到 新建，保存，刷新，取消这几个BUTTON。Mediar.framework 把所有的对象看归纳成只有这几个操作，通过这几个操作来控制对象。这几个button的事件调用活动窗口中的相应方法，最后调用对应的对象中相关方法.

 

主窗体中:    

private void toolStripBase_ItemClicked(object sender, ToolStripItemClickedEventArgs e)

        {

            BizObjectBoundEdit m = this.ActiveMdiChild as BizObjectBoundEdit;

 

            switch (e.ClickedItem.Name)

            {

                case "toolStripButtonNew":

                    m.NewButtonPressed();

                    ActiveMenu();

                    break;

                case "toolStripButtonCancel":

                    m.CancelButtonPressed();

                    break;

                case "toolStripButtonSave":

                    m.UpdateButtonPressed();

                    break;

                case "toolStripButtonRefresh":

                    m.RefreshButtonPressed();

                    break;

            }

        }

 

 所有的对象UI都继承一个基础窗体，下面的方法作为共用方法写在这个基础窗体中。mRootBizObject 为窗体中对应的对象实体。这里就讲的比较的粗枝大叶了，不然决对不是一个短短的文章可以写清楚的。

      

public virtual void NewButtonPressed()

         {

              this.Cursor = Cursors.WaitCursor;

              if (mRootBizObject == null) 

              {

                   ChangeRootBizObject(this.CreateNewBizObject(null));

              } 

              else 

              {

                   ChangeRootBizObject(this.CreateNewBizObject(mRootBizObject.GetType()));

              }

              DisplayObject(mRootBizObject);

              this.Cursor = Cursors.Default;

         }

 

        public virtual void CancelButtonPressed()

         {

              this.Cursor = Cursors.WaitCursor;

              mRootBizObject.CancelEdit();

              DisplayObject(mRootBizObject);

              this.Cursor = Cursors.Default;

         }

 

        public virtual bool UpdateButtonPressed()

         {

              bool retVal;

              this.Cursor = Cursors.WaitCursor;

              if (mRootBizObject.Update()) 

              {

                   retVal = true;

              } 

              else 

              {

                   retVal = false;

                   MessageBox.Show("Your changes were NOT saved.  Please review any error messages and try your save again.", mFriendlyClassName, MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1);

              }

              this.Cursor = Cursors.Default;

              return retVal;

         }   

 

        public virtual void RefreshButtonPressed()

         {

              this.Cursor = Cursors.WaitCursor;

              mRootBizObject.ReSelect();

              this.Cursor = Cursors.Default;

         }

 

新建需要通过工厂中的 CreateBizObject方法，因为每个对象都需要包括一个工厂，就需要在新建的时候构造传入。对象新建可以在InitializeValues方法设对象default 值。

 

public BizObject CreateBizObject()

         {

              BizObject bo;

              bo = CreateBizObject(this);

              UpdateCache(bo);

              return bo;

         }

 

protected override BizObject CreateBizObject(BizObjectFactory bof)

        {

            return new Contact(bof);

        }

 

 

 

 

取消就把Original值覆盖到当前值.

    

 public void CancelEdit()

         {

              CancelEditChildren();

              if ((mIsDirty)) 

              {

                   RestoreLastPersistedValues();

                   this.OnBizObjectUpdatedEvent(new BizObjectUpdatedEventArgs(BizObjectUpdatedType.Changed));

              }

         }

 protected override void RestoreLastPersistedValues()

        {

            mDisplayID[AttributeValueVersion.Current] = mDisplayID[AttributeValueVersion.Original];

            mFirstName[AttributeValueVersion.Current] = mFirstName[AttributeValueVersion.Original];

            mLastName[AttributeValueVersion.Current] = mLastName[AttributeValueVersion.Original];

            mDescription[AttributeValueVersion.Current] = mDescription[AttributeValueVersion.Original];

            mCompanyName[AttributeValueVersion.Current] = mCompanyName[AttributeValueVersion.Original];

            mContactType[AttributeValueVersion.Current].UniqueID = mContactType[AttributeValueVersion.Original].UniqueID;

          // mAddress[AttributeValueVersion.Current].UniqueID = mAddress[AttributeValueVersion.Original].UniqueID;

            mEmailAddress[AttributeValueVersion.Current] = mEmailAddress[AttributeValueVersion.Original];

            mWebSiteURL[AttributeValueVersion.Current] = mWebSiteURL[AttributeValueVersion.Original];

            mNotes[AttributeValueVersion.Current] = mNotes[AttributeValueVersion.Original];

 

            base.RestoreLastPersistedValues();

        }

 

保存就把数据更新到数据库，然后再刷新当前的实体。也许有人要问：刚才保存的为什么要刷新呀？刷新目是把RecordVersion取出来，RecordVersion是timestamp类型，每更新一次数据库，该字段就是有一个新值。在更新数据库之前会和数据库中的值比较，这是防止两个人在同时修改一个对象时引发冲突。

    

public virtual bool Update(string AssemblyName)

         {

            BeginEdit();

              DataSet ds;

              DataRow dr;

              BizObject bobjClone;

              bool success = false;

              if (!mAllowEdit) 

              {

                   throw new Exception("Object marked to disallow edits");

              }

              if (!Validate()) 

              {

                   return false;

              }

 

              ds = mBOFactory.CreateDataObject();

              dr = GetDataObjectRow(ds);

       

              try 

              {

                mBOFactory.Update( ref ds, AssemblyName);

           

                   success = !(ds.HasErrors);

                   if ((ds.HasErrors && DBUtility.HasDBConcurrencyError(ds))) 

                   {

                       bobjClone = this.Clone(true);

                       OnBizObjectConcurrencyErrorEvent(new BizObjectConcurrencyErrorEventArgs(bobjClone));

                   } 

                   else 

                   {

                       Refresh(ds);

                   }

              } 

              catch (CustomBizObjectException ex) 

              {

                   ExceptionManager.Publish(ex);

                   throw ex;

              } 

              catch (Exception ex) 

              {

                   success = false;

                   this.OnBizObjectErrorEvent(new BizObjectErrorEventArgs(BizObjectErrorType.DBError, ex.Message, ""));

              }

 

            this.EndEdit();

              return success;

 

         }

 

Factory类中，就会调用数据层的更新方法。

  

 public void Update(ref DataSet ds, string AssemblyName)

        {

            DataAccess da;

            da = GetDataAccess(AssemblyName);

            ds= da.Update(ds,true);

        }

刷新就是从数据库重取数据，然后更新对象属性的值。

 

 

public virtual void ReSelect()

         {

              this.ReSelect(QueryFor.Complete);

         }

 

         public virtual void ReSelect(QueryFor queryFor)

         {

              if (this.mIsDirty) 

              {

                   throw new CustomBizObjectException("Can not ReSelect if BizObject is dirty.");

              }

              this.mBOFactory.ReSelect(this, queryFor, mDataAccessAssemblyName);

         }

     // mBOFactory 中

     protected internal void ReSelect(BizObject bobj, QueryFor queryFor, string DAAssemblyName)

         {

              DataSet ds;

              ds = this.GetDataAccess(DAAssemblyName).Select(bobj.UniqueID, QueryFor.Complete);

              this.BuildBizObject(bobj.UniqueID, ds, queryFor);

         }