List of components and classes
EhLib contains components and classes for Borland Delphi, CodeGear Delphi & C++ Builder, CodeGear RAD Studio, Embarcadero RAD Studio, intended to increase capacity of the client part of database application in part of interaction with applications user.
Provides all functionality of TDBGrid and adds several new features as follows:
Allows to select records, columns and rectangle areas.
Special titles that can correspond to several/all columns.
Footer that is able to show sum/count/other field values.
Automatic column resizing to set grid width equal client width.
Ability to change row and title height.
Allows automatic broken of a single line long title and data row to a multiline.
Title can act as button and, optionally show a sort marker.
Ability to truncate long text with ellipsis.
Lookup list can show several fields.
Incremental search in lookup fields.
DateTime picker support for TDateField and TDateTimeField.
Allows to show bitmaps from TImageList depending on field value.
Allows to hide and track horizontal or vertical scrollbars.
Allows to hide columns.
Allows to show 3D frame for frozen, footer and data rows.
Allows to draw memo fields.
Multiline inplace editor.
Proportional scrolling independently of sequenced of dataset.
Automatically show checkboxes for Boolean fields. Allows to show checkboxes for other type of fields.
Has a procedures to save and restore layout (visible columns, columns order, columns width, sortmarkers, row height) in/from registry or ini file.
Allows to show hint (ToolTips) for text that don't fit in the cell.
Allows to export data to Text, Csv, HTML, RTF, XLS and internal formats.
Allows to import data from Text and internal formats.
Can sort data in various dataset's.
Can filter data in various dataset's.
When DBGridEh is connected to DataSet of TMemTable type it allows:
To view all data without moving active record.
To display a tree-type structure of TMemTable records.
To form list of values in dropdown list of SubTitle filter automatically.
To group data using columns as a criterion of grouping.
TPrintDBGridEh provides properties and routines for preview and print of TDBGridEh component with several features:
Ability to expand rows vertically until all text is printed.
Ability to scale grid to fit it to page width.
Ability to print/preview title for grid.
Ability to print/preview page header and page footer where you can specify macros for current page, current date, current time and/or static text.
Automatically print/preview multiselected area of TDBGridEh if it area is not empty.
Ability to print/preview rich text before and after grid.
Component to show one record from dataset in Vertical Orientation.
Have a special column to show Field Captions
Can customize inplace editor and data of the cell like in DBGridEh.
Provides all functionality of TDBLookupCombobox and adds several new features as follows:
Can have flat style.
Allows assign values as to KeyValue property just and to display Text property.
Allows to type (assign) values to Text property not contained in data list (Style = csDropDownEh).
Allows to hold KeyValue and Text as not affecting to each other values.
Take effect when KeyField, ListField, ListSource, DataField and DataSource properties is empty.
Drop down list can:
Have sizing grip,
Automaticaly set width as sum of DisplayWidth of the list fields (Width = -1),
Automaticaly drops on user pressed the key.
Edit button can:
Show DropDown, Ellipsis or Bitmap image.
Have specified width.
Have additional events: OnKeyValueChanged, OnButtonClick.
Represents a single or multi-line edit control that can display and edit a field in a dataset or can works as non data-aware edit control.
Pepresents a single-line date or time edit control that can display and edit a datetime field in a dataset or can works as non data-aware edit control.
Represents a single or multi-line edit control that combines an edit box with a scrollable list and can display and edit a field in a dataset or can works as non data-aware combo edit control.
Represents a single-line number edit control that can display and edit a numeric field in a dataset or can works as non data-aware edit control.
Is intended for totaling sums and amounts of records in a TDataSet with dynamic changes. Component keeps a list of TDBSum objects, which contains types of group operations (goSum or goCount) and name sum field (goCount name of field is unnecessary).
TPreviewBox lets you create a customizable runtime preview.
TPreviewBox lets you create a customizable runtime preview.
TPrinterPreview lets you to record printable data in buffer for following output them on screen and to printer. TPrinterPreview have all functions and properties as in TPrinter object. You can use TPrinterPreview object similarly of TPrinter except some details. In TPrinter Printer.Canvas.Handle and Printer.Handle is the same but in TPrinterPreview PrinterPreview.Canvas.Handle represent the metafile in that is recored the data and PrinterPreview.Handle represent Printer.Handle. That is mean that you have to use PrinterPreview.Canvas.Handle for draw operation (DrawText, DrawTexteEx, e.t.c.) and use PrinterPreview.Handle in functions that return information about printer facilities (GetDeviceCaps, e.t.c.). Global function PrinterPreview returns default PrinterPreview object and shows data in default preview form.
Components realize technology to store component properties to/from settings storage such as ini files, registry etc.
TMemTableEh - dataset, which hold data in memory. Its possible consider as an array of records.
Supports a special interface, which allows DBGridEh component to view all data without moving active record.
Allows fetch data from TDataDriverEh object (DataDriver property).
Allows unload change back in DataDriver, operative or postponed (in dependencies of the CachedUpdates property).
Allows to create a master/detail relations on the client (filtering record) or on the external source (updating parameters [Params] and requiring data from DataDriver).
Allows once-only (without the dynamic support) sort data, including Calculated and Lookup field.
Allows create and fill data in design-time and save data in dfm file of the Form.
Allows keep record in the manner of trees. Each record can have record elements-branches and itself be an element to other parental record. Component TDBGridEh supports to show the tree-type structure of these records.
Allows to connect to the internal array of other TMemTableEh (via ExternalMemData property) and work with its data: sort, filter, edit.
Has interface for requesting list of all unique values in one column of records array, ignoring local filter of the DataSet. TDBGridEh uses this property for automatic filling a list in DropDownBox of the subtitle filter cell.
TDataDriverEh - carry out two tasks:
1. Delivers data to TMemTableEh.
2. Processes changed records of TMemTableEh (writes them in other dataset, or call events for processing the changes in program).
Furthermore, there are several components that inherited from TDataDriverEh. It is a TSQLDataDriverEh, that have properties to keep four SQL expressions and parameters to: query data, delete record, insert record, updat record and requery one record. TSQLDataDriverEh can not interact with server by itself, but can prepare parameters for request and call global event to transfer SQL expression on processing in application. There are several components that inherited from TSQLDataDriverEh, which can send SQL expressions on the server through the corresponding access engine. It is a TBDEDataDriverEh, TIBXDataDriverEh, TDBXDataDriverEh and TADODataDriverEh components.
DataDriver, that delivers records in TMemTableEh from other DataSet. Processes records, changed in TMemTableEh writing them in other DataSet.
TSQLDataDriverEh is a universal driver of data which interact with server by means of SQL. TSQLDataDriverEh have five objects of the TSQLCommandEh type: SelectCommand, DeleteCommand, InsertCommand, UpdateCommand, GetrecCommand. Each object holds SQL expressions and parameters to execute command to, accordingly, query data, delete record, insert record, update record and get record. To execute command, TSQLDataDriverEh calls global event - DefaultSQLDataDriverResolver.OnExecuteCommand. You should write this event to execute SQL expressions on the server and, if need, return DataSet to read data. When TSQLDataDriverEh is used as provider of data, it takes records from DataSet created in DefaultSQLDataDriverResolver.OnExecuteCommand event and writes them in TMemTableEh. On the measure of the requirement it takes given current record, writes them in TMemTableEh and goes over to following record. When TSQLDataDriverEh is used as handler of changes, it takes a changed record from TMemTableEh, and call DefaultSQLDataDriverResolver.OnExecuteCommand event sending DeleteCommand, InsertCommand or UpdateCommand as a parameter.
DataDriver, which interacts with the DB server using BDE data driver. TBDEDataDriverEh has one additional property - Database of TDatabase type. This property specify a connection, through which DataDriver will send queries for the server.
DataDriver, which interacts with the DB server using IBX data driver. TIBXDataDriverEh has one additional property - Database of TIBDatabase type. This property specify a connection, through which DataDriver will send queries for the server.
DataDriver, which interacts with the DB server using DBX data driver. TDBXDataDriverEh has one additional property - SQLConnection of TSQLConnection type. This property specify a connection, through which DataDriver will send queries for the server.
DataDriver, which interacts with the DB server using ADO data driver. TADODataDriverEh has one additional property - ADOConnection of TADOConnection type. This property specify a connection, through which DataDriver will send queries for the server.