Difference between revisions of "Midware TMWTable"

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| valign="top" | [[Midware_TMWTable.BeforeCancel | BeforeCancel]] |||| Occurs before an application executes a request to cancel changes to the current record.  
 
| valign="top" | [[Midware_TMWTable.BeforeCancel | BeforeCancel]] |||| Occurs before an application executes a request to cancel changes to the current record.  
 
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| valign="top" | [[Midware_TMWTable.BeforeClose | BeforeClose]] |||| Write a BeforeClose event to take specific action before an application closes a dataset.  
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| valign="top" | [[Midware_TMWTable.BeforeClose | BeforeClose]] |||| Occurs before an application executes a request to close the dataset.
 
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| valign="top" | [[Midware_TMWTable.BeforeDelete | BeforeDelete]] |||| Write a BeforeDelete event handler to take specific action before an application deletes the current record.
 
| valign="top" | [[Midware_TMWTable.BeforeDelete | BeforeDelete]] |||| Write a BeforeDelete event handler to take specific action before an application deletes the current record.

Revision as of 11:39, 24 May 2011

Main page -> Midware component reference -> TMWTable

Overview

unit MWdatSet.pas

TMWTable component is much like standard Delphi TTable or TQuery components. TMWTable is used as an interface between data and your program or visual interface.

TMWTable is a TDataSet descendent so you can use it with data-aware controls such as TDBEdit and TDBGrid. Just like you use TQuery or TTable.

TMWTable is an interface that present MidWare communication buffer (TMWBuffer component) as a standard Delphi data table. It let you navigate thru all records and fields. You can and locate data, insert, delete or edit data. TMWTable has no storage for data: all data is stored in TMWBuffer component.

TMWTable has no knowledge of table structure. You must specify it using FieldLayout property. You can fill this property at design time if you know what it will be at runtime, or you may fill it at runtime once you know the value. The value may be known at runtime because your client application query the application server for field layout. You may also sent field layout in first record in result set, feed it to the property and then delete it from result set.

Properties

Active Active property is TRUE when TMWTable is opened and FALSE when TMWTable is closed.
AppSrvClient To execute a request at design time, TMWTable need an TAppSrvClient component which will handle communication with MidWare application server.
AutoCalcFields Set AutoCalcFields to control when the OnCalcFields event is triggered to update calculated fields during dataset processing.
CanModify CanModify readonly property returns TMWTable ReadOnly value.
Data Data property is a link to TMWBuffer component used to hold all data.
FieldLayout FieldLayout property is used to describe columns content.
FunctionCode FunctionCode and Params properties are the design time request. It's main purpose is to populate data aware controls link to TMWTable at design time. It can also be executed at runtime using ExecuteRequest.
MWBufferFieldCount The number of fields. Based on FieldLayout property.
ReadOnly ReadOnly property is used to get or set TMWTable read only status. See also CanModify.
RecordSize The record size property gives the size of the record.
Params FunctionCode and Params properties are the design time request.
TimeOut When executing a request at design time, TMWTable will stop waiting for answer after Timeout seconds.

Methods

Close Close the communication with the application server.
CreateBlobStream Call CreateBlobStream to obtain a stream for reading and writing the value of the field specified by the Field parameter.
DesignTimeRequest DesignTimeRequest procedure will execute the request specified at design time.
ExecuteRequest Call ExecuteRequest procedure to execute design time request.
Locate Implements a method for searching a dataset for a specified record and makes that record the current record.
Lookup Implements a method to retrieve field values from a record that matches specified search values.
Send Send a FunctionCode and Request (parmeters) to the application server.

Events

AfterCancel Occurs after an application completes a request to cancel modifications to the current record.
AfterClose Occurs after an application closes a dataset.
AfterDelete Occurs after an application deletes a record.
AfterEdit Occurs after an application starts editing a record.
AfterInsert Occurs after an application inserts a new record.
AfterOpen Occurs after an application completes opening a dataset and before any data access occurs.
AfterScroll Occurs after an application scrolls from one record to another.
BeforeCancel Occurs before an application executes a request to cancel changes to the current record.
BeforeClose Occurs before an application executes a request to close the dataset.
BeforeDelete Write a BeforeDelete event handler to take specific action before an application deletes the current record.
BeforeEdit Write a BeforeEdit event handler to take specific action before an application enables editing of the current record.
BeforeInsert Write a BeforeInsert event handler to take specific action before an application inserts or appends a new record.
BeforeOpen Write an AfterOpen event handler to take specific action immediately after an application opens the dataset.
BeforeScroll Write a BeforeScroll event handler to take specific action immediately after an application scrolls to another record as a result of a call to the First, Last, MoveBy, Next, Prior, FindKey, FindFirst, FindNext, FindLast, FindPrior, and Locate methods.
OnCalcField Write an OnCalcFields event handler to take specific action when an application recalculates calculated fields.
OnDisplayInfo This is used for debugging purpose and should normally not be used in an application.
OnDeleteError Write an OnDeleteError event handler to handle exceptions that occur when an attempt to delete a record fails.
OnEditError Write a BeforeEdit event handler to take specific action before an application enables editing of the current record.
OnNewRecord Write an OnNewRecord event handler to take specific actions as an application inserts or appends a new record.
OnPostError Write an OnPostError event handler to handle exceptions that occur when an attempt to edit a record fails.
OnRequestDone When design time request has been executed, then event OnRequestDone is triggered.

How To


Midware Components Reference