TcxGridDBColumn Class

A column in a data-aware grid Table View.

Declaration

TcxGridDBColumn = class(
    TcxGridColumn
)

Remarks

A column in a data-aware Table View is designed to display values from a dataset field. Use the DataBinding property to bind a data-aware column to data.

VCL Data Grid: A Table View Column Example

In-Place Editors

A column can use any editor shipped with the ExpressEditors Library as an in-place editor for cell edit operations. An in-place editor instance exists (and, therefore, consumes memory and other system resources, such as a WinAPI handle) only when a column cell is being edited. Otherwise, the column displays a static editor image for resource usage optimization.

To switch between available editors, you can use the PropertiesClassName or PropertiesClass property. Use the Properties property to configure the in-place editor associated with the column.

Default In-Place Editor and Data Types

When PropertiesClassName and PropertiesClass properties are unspecified, the data type of the underlying dataset field determines the active in-place editor according to the following table:

Dataset Field Type	Default In-Place Editor	Description
`ftBoolean`	TcxCheckBox	A check box editor with support for three states.
`ftCurrency`, `ftBCD`, and `ftFMTBcd`	TcxCurrencyEdit	A numeric editor for currency values.
`ftDate` and `ftDateTime`	TcxDateEdit	A date editor with a drop-down calendar.
`ftTime`	TcxTimeEdit	A spin editor for time values.
`ftBytes`, `ftVarBytes`, `ftBlob`, `ftFmtMemo`, `ftParadoxOle`, `ftDBaseOle`, and `ftTypedBinary`	TcxBlobEdit	A Binary Large Object (BLOB) editor.
`ftMemo`	TcxMemo	A multi-line editor for plain text.
`ftGraphic`	TcxImage	An editor designed to display images.
All other types	TcxMaskEdit	A single-line text editor with support for input masks.

Main API Members

The list below outlines key members of the TcxGridDBColumn class that allow you to configure columns in a data-aware grid Table View.

Bind the column to data (DataBinding).
Fix the column or dock it to the left when users scroll the grid’s Table View to the right (FixedKind).
Identify if the column is selected (Selected).
Specify a caption for the column (Caption).
Define an alternative caption for the column (AlternateCaption.
Identify if the column is the first or last visible column in the parent grid View (IsFirst and IsLast).
Hide or display the column (Visible).
Switch between available in-place editor types (PropertiesClass and PropertiesClassName).
Configure the assigned in-place editor (Properties and RepositoryItem).
Activate and deactivate the assigned in-place cell editor (Editing).
Adjust the column width to display content in full (ApplyBestFit).
Sort data against the column (SortIndex and SortOrder).
Group columns in the grid Table View (GroupIndex).
Scroll the grid Table View to display the column (MakeVisible).
Display custom cell value display text (OnGetDisplayText).
Configure column summaries (Summary).
Customize the appearance of column elements (Styles).
Position column footer cells (FooterAlignmentHorz).
Specify if the column is visible in an in-place Edit Form and the custom row layout (VisibleForEditForm and VisibleForRowLayout).
Access the layout item that hosts the column’s editor in an in-place Edit Form (LayoutItem).
Identify the column’s position in the parent grid View or a band (IsBottom, IsLeft, IsMostBottom, IsMostLeft, IsMostRight, IsRight, and IsTop).
Assign a glyph to the column’s header (HeaderGlyph and HeaderImageIndex).
Customize column appearance and behavior settings (Options).
Position the glyph within the column header (HeaderGlyphAlignmentHorz and HeaderGlyphAlignmentVert).
Configure the column’s container item in a custom row layout (RowLayoutItem).
Identify if the column has a preview section (IsPreview).
Access the grid Table View to which the column belongs (GridView).
Custom draw the column (OnCustomDrawCell).
Apply styles to different column elements (Styles.
Adjust the minimum column width (MinWidth).
Customize column captions displayed in a filter drop-down window (OnGetFilterDisplayText).
Position the column header horizontally and vertically (HeaderAlignmentHorz and HeaderAlignmentVert.

Example: Create a Data-Aware Column

The following code example creates a data-aware column, associates it with a field in the dataset bound to the parent grid Table View, sets a single-line text editor as the column’s in-place editor, and customizes editor settings:

Delphi
C++

uses cxTextEdit;
// ...
var
  AColumn: TcxGridDBColumn;
  ATextEditProperties: TcxTextEditProperties;
begin
  AColumn := cxGrid1DBTableView1.CreateColumn;  // Creates a new data-aware column
  AColumn.DataBinding.FieldName := 'ContactName'; // Binds the created column to the "ContactName" field
  AColumn.PropertiesClass := TcxTextEditProperties; // Assigns an in-place single-line text editor
  ATextEditProperties := AColumn.Properties as TcxTextEditProperties;
  ATextEditProperties.Nullstring := 'Add a contact name'; // Prompts users to enter a contact name
  ATextEditProperties.UseNullString := True;  // Displays the defined text hint in an empty editor
  ATextEditProperties.MaxLength := 30;  // Limits the maximum contact name length
end;

#include "cxTextEdit.hpp"
// ...
  TcxGridDBColumn *AColumn;
  TcxTextEditProperties *ATextEditProperties;
  // ...
  AColumn = cxGridDBTableView1->CreateColumn();  // Creates a new data-aware column
  AColumn->DataBinding->FieldName = "ContactName"; // Binds the created column to the "ContactName" field
  AColumn->PropertiesClass = __classid(TcxTextEditProperties); // Assigns an in-place single-line text editor
  ATextEditProperties = dynamic_cast<TcxTextEditProperties*>(AColumn->Properties);
  ATextEditProperties->Nullstring = "Add a contact name"; // Prompts users to enter a contact name
  ATextEditProperties->UseNullString = true;  // Disables the defined hint text in an empty editor
  ATextEditProperties->MaxLength = 30;  // Limits the maximum contact name length

Direct TcxGridDBColumn Class References

The following public API members reference a TcxGridDBColumn object:

TcxGridDBTableView.Columns: Provides indexed access to the collection of the View’s columns.
TcxGridDBTableView.CreateColumn: Creates and adds a column to the View’s Columns collection.
TcxGridDBTableView.GetColumnByFieldName: Locates the column displaying a particular field’s values.