Class GridComboBoxCellRenderer

Implements the renderer part of a combo box cell.

Inheritance
System.Object
NonFinalizeDisposable
GridCellRendererBase
GridStaticCellRenderer
GridTextBoxCellRenderer
GridDropDownCellRenderer
GridComboBoxCellRenderer
GridTableFilterBarExtCellRenderer
GridTableFilterBarCellRenderer
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: Syncfusion.Windows.Forms.Grid
Assembly: Syncfusion.Grid.Windows.dll
Syntax
public class GridComboBoxCellRenderer : GridDropDownCellRenderer, IQueryFocusInside, IGridDropDownCell, IPopupParent, IPopupItem, IDisposable
Remarks

GridComboBoxCellRenderer can be customized with DataSource, ValueMember, and DisplayMember properties of a GridStyleInfo instance.

If you do not have a data source object, you can also fill the drop-down list contents with a ChoiceList and optionally specify ExclusiveChoiceList.

The combo box cell is XP Themes enabled. It will be drawn themed if ThemesEnabled is True.

There can be several renderers associated with one GridComboBoxCellModel if several views display the same GridModel.

Use "ComboBox" as identifier in CellType of a cells GridStyleInfo to associate this cell type with a cell.

The cell's behavior and appearance can be customized with the following properties of the GridStyleInfo class:

PropertyNameDescription
AllowEnter (System.Boolean)Gets / sets if pressing the <Enter>-Key should insert a new line into the edited text. (Default: False)
BaseStyle (System.String)The base style for this style instance with default values for properties that are not initialized for this style object. (Default: String.Empty)
Borders (GridBordersInfo)Top, left, bottom, and right border settings. (Default: GridBordersInfo.Default)
CellAppearance (GridCellAppearance)Specifies if cell edges should be drawn raised, sunken, or flat (default). (Default: GridCellAppearance.Flat)
CellTipText (System.String)ToolTip text to be displayed when user hovers mouse over cell. (Default: String.Empty)
CellType (System.String)Combo Box (Default: Text Box)
CellValue (System.Object)This property holds the cell value. Although the cell value is typically a string, it can also be any other primitive type such as int, byte, enum, or any custom type that is derived from System.Object. (Default: String.Empty)
CellValueType (System.Type)Specifies the preferred System.Type for cell values. When you assign a value to the GridStyleInfo object, the value will be converted to this type. If the value cannot be converted, Error will contain error information. (Default: NULL)
ChoiceList (System.Collections.Specialized.StringCollection)Specifies items to be displayed in the drop-down list. (Default: NULL)
Clickable (System.Boolean)Specifies if the combo box button can be clicked. If set to False, the button will be drawn grayed out. See Enabled for information on how to disable activating the combo box cell. (Default: True)
CultureInfo (System.Globalization.CultureInfo)The culture information holds rules for parsing and formatting the cell's value. (Default: NULL)
DataSource (System.Object)Specifies a data source that holds items to be displayed in a drop-down list. A data source can be specified instead of manually filling the choicelist with string entries. (Default: NULL)
DisplayMember (System.String)Names the property in the data source that holds the text to be displayed in a cell that depends on a ValueMember. (Default: String.Empty)
DropDownStyle (GridDropDownStyle)Specifies if user input is restricted to items from the ChoiceList or DataSource. (Default: GridDropDownStyle.Editable)
Enabled (System.Boolean)Specifies if the cell can be activated as current cell or if cell should be skipped when moving the current cell. When disabled, the combo box button can still be clicked but no drop-down list is displayed. You should also disable Clickable if you do not want the user to click the combo box button. (Default: True)
Error (System.String)Holds error information if a value can not be converted to the System.Type specified with CellValueType. (Default: String.Empty)
ExclusiveChoiceList (System.Boolean)Specifies if user input is restricted to items from choice list or data source. It is recommended to use DropDownStyle instead. (Default: False)
Font (GridFontInfo)The font for drawing text. (Default: GridFontInfo.Default)
HorizontalAlignment (GridHorizontalAlignment)Specifies horizontal alignment of text in the cell. This does not affect the position of the combo box button. (Default: GridHorizontalAlignment.Left)
ImageIndex (System.Int32)Specifies an index for a image in the ImageList of a GridStyleInfo instance. The image is currently only shown in the text field, not in the drop-down list. You have to add custom programming logic in order to set the ImageIndex based on a selection in the drop-down list. (Default: -1)
Interior (BrushInfo) Lets you specify a solid back color, gradient, or pattern style with both back and fore color for a cell's background. (Default: SystemColors.Window)
ReadOnly (System.Boolean)Specifies if cell contents can be modified by the user. The user can still drop-down the combo box but changes will not be saved back into the text field. (Default: False)
ShowButtons (GridShowButtons)Specifies when to show or display the combo box button. Possible choices are: show the button only for the current cell, always show buttons, or never show buttons. (Default: GridShowButtons.Show)
Text (System.String)Gets / sets the value as a string. If a CellValueType is specified, the text will be parsed and converted to the type specified with CellValueType using any CultureInfo information. (Default: String.Empty)
TextAlign (GridTextAlign)Align text left of button elements (which is typical for combo boxes). Or align text right of button elements. (Default: GridTextAlign.Default)
TextColor (System.Drawing.Color)Lets you specify the color for drawing the cell text. (Default: SystemColors.WindowText)
TextMargins (GridMarginsInfo)Holds text margins in pixels. When drawing a cell, this specifies the empty area between the text rectangle and the borders of the client rectangle of the cell. The client rectangle is the cell rectangle without buttons and borders. (Default: GridMarginsInfo.Default)
Themed (System.Boolean)Specifies if cell should be drawn using Windows XP themes when ThemesEnabled has been set. (Default: True)
Trimming (System.Drawing.StringTrimming)Indicates how text is trimmed when it exceeds the edges of the cell text rectangle. (Default: StringTrimming.Character)
ValidateValue (GridCellValidateValueInfo)Holds validation rules for the cell value that are being checked before any user changes are committed to the grid cell's style object. (Default: NULL)
ValueMember (System.String)Names the property in the data source that holds the key to be saved in a cell. (Default: String.Empty)
VerticalAlignment (GridVerticalAlignment)Specifies vertical alignment of text in the cell. (Default: GridVerticalAlignment.Top)
WrapText (System.Boolean)Specifies if text should be wrapped when it does not fit into a single line. (Default: True)

Constructors

GridComboBoxCellRenderer(GridControlBase, GridCellModelBase)

Initializes a new GridComboBoxCellRenderer object for the given GridControlBase and GridCellModelBase.

Declaration
public GridComboBoxCellRenderer(GridControlBase grid, GridCellModelBase cellModel)
Parameters
Type Name Description
GridControlBase grid

The GridControlBase that display this cell renderer.
GridCellModelBase cellModel

The GridComboBoxCellModel that holds data for this cell renderer that should be shared among views.
Remarks

References to GridControlBase, and GridCellModelBase will be saved.

Properties

AllowValidateStringOnKeyPress

Gets or sets a value indicating whether the combo box should raise CurrentCellValidateString notifications when the user types into the combo box. Default is true.

Declaration
public bool AllowValidateStringOnKeyPress { get; set; }
Property Value
Type
System.Boolean
Remarks

Note: In version 3.3 and earlier the combo box did not raise these notifications. To maintain compatibility this option allows you to turn off this behavior.

ControlText

Gets or sets the active text that is displayed on the cell.

Declaration
public override string ControlText { get; set; }
Property Value
Type
System.String
Overrides

ListBoxPart

Gets or sets the System.Windows.Forms.ListBox that is displayed when the user drops-down the combo box.

Declaration
public ListBox ListBoxPart { get; set; }
Property Value
Type
System.Windows.Forms.ListBox

Model

Gets the GridComboBoxCellModel that this cell renderer belongs to.

Declaration
public GridComboBoxCellModel Model { get; }
Property Value
Type
GridComboBoxCellModel

Methods

AttachListBoxPart()

Called to attach a list box part to this renderer object.

Declaration
protected virtual void AttachListBoxPart()

ChildClosing(IPopupChild, PopupCloseType)

Occurs when the popup child is being closed.

Declaration
public override void ChildClosing(IPopupChild childUI, PopupCloseType popupCloseType)
Parameters
Type Name Description
IPopupChild childUI

The pop up.
PopupCloseType popupCloseType

The way in which the pop up is closed.
Overrides

CreateListBoxPart()

Creates a GridComboBoxListBoxPart that is used as list box inside the drop-down.

Declaration
protected virtual ListBox CreateListBoxPart()
Returns
Type Description
System.Windows.Forms.ListBox

A GridComboBoxListBoxPart that is derived from System.Windows.Forms.ListBox

DetachListBoxPart()

Called to detach the list box part from this renderer object.

Declaration
protected virtual void DetachListBoxPart()

Dispose(Boolean)

Declaration
protected override void Dispose(bool disposing)
Parameters
Type Name Description
System.Boolean disposing
Overrides

DropDownContainerShowedDropDown(Object, EventArgs)

Occurs after the pop up has been dropped down and made visible.

Declaration
public override void DropDownContainerShowedDropDown(object sender, EventArgs e)
Parameters
Type Name Description
System.Object sender

Combobox cell renderer.
System.EventArgs e

The event args.
Overrides

DropDownContainerShowingDropDown(Object, CancelEventArgs)

Occurs when the drop down is about to be shown.

Declaration
public override void DropDownContainerShowingDropDown(object sender, CancelEventArgs e)
Parameters
Type Name Description
System.Object sender

Combobox cell renderer.
System.ComponentModel.CancelEventArgs e

Event args.
Overrides

FindItem(String, Boolean, Int32, Boolean)

Finds text in the list box.

Declaration
public virtual int FindItem(string prefix, bool selectItem, int start, bool ignoreCase)
Parameters
Type Name Description
System.String prefix

The text (or prefix) to find.
System.Boolean selectItem

True if you want to select the text in the list box.
System.Int32 start

The first index to start searching.
System.Boolean ignoreCase

True if case can be ignored; False if case sensitive.
Returns
Type Description
System.Int32

The index of the entry that starts with the text; -1 if no entry could be found.

FindItemExact(String, Boolean, Int32, Boolean)

Finds text in the list box.

Declaration
public virtual int FindItemExact(string text, bool selectItem, int start, bool ignoreCase)
Parameters
Type Name Description
System.String text

The text (or prefix) to find.
System.Boolean selectItem

True if you want to select the text in the list box.
System.Int32 start

The first index to start searching.
System.Boolean ignoreCase

True if case can be ignored; False if case sensitive
Returns
Type Description
System.Int32

The index of the entry that starts with the text; -1 if no entry could be found.

InitializeDropDownContainer()

Overridden to initialize drop down container.

Declaration
protected override void InitializeDropDownContainer()
Overrides

ListBoxClick(Object, EventArgs)

Handles the System.Windows.Forms.Control.Click event of the list box.

Declaration
protected virtual void ListBoxClick(object sender, EventArgs e)
Parameters
Type Name Description
System.Object sender

The source of the event.
System.EventArgs e

An System.EventArgs with event data.

ListBoxMouseUp(Object, MouseEventArgs)

Handles the System.Windows.Forms.Control.MouseUp event of the list box.

Declaration
protected virtual void ListBoxMouseUp(object sender, MouseEventArgs e)
Parameters
Type Name Description
System.Object sender

The source of the event.
System.Windows.Forms.MouseEventArgs e

A System.Windows.Forms.MouseEventArgs with event data

NotifyCurrentCellChanged()

Overridden to call the NotifyCurrentCellChanged() method.

Declaration
protected override void NotifyCurrentCellChanged()
Overrides

OnClick(Int32, Int32, MouseEventArgs)

Invoked when the user clicked inside a cell.

Declaration
protected override void OnClick(int rowIndex, int colIndex, MouseEventArgs e)
Parameters
Type Name Description
System.Int32 rowIndex

The row index.
System.Int32 colIndex

The column index.
System.Windows.Forms.MouseEventArgs e

A System.Windows.Forms.MouseEventArgs with data about the mouse event.
Overrides

OnDeactivating()

Closes the DropDown if the CurrentCell is deactivated along with BrowseOnly property

Declaration
protected override bool OnDeactivating()
Returns
Type
System.Boolean
Overrides

OnDoubleClick(Int32, Int32, MouseEventArgs)

Called when the user double-clicks inside a cell.

Declaration
protected override void OnDoubleClick(int rowIndex, int colIndex, MouseEventArgs e)
Parameters
Type Name Description
System.Int32 rowIndex

The row index.
System.Int32 colIndex

The column index.
System.Windows.Forms.MouseEventArgs e

A System.Windows.Forms.MouseEventArgs with data about the mouse event.
Overrides

OnEditPartMouseDown(Object, MouseEventArgs)

Handles the System.Windows.Forms.Control.MouseDown event of the active text box.

Declaration
protected virtual void OnEditPartMouseDown(object sender, MouseEventArgs e)
Parameters
Type Name Description
System.Object sender

The source of the event.
System.Windows.Forms.MouseEventArgs e

An System.Windows.Forms.MouseEventArgs with event data.

OnInitialize(Int32, Int32)

Overridden to initialize the list box style and value.

Declaration
protected override void OnInitialize(int rowIndex, int colIndex)
Parameters
Type Name Description
System.Int32 rowIndex
System.Int32 colIndex
Overrides

OnKeyDown(KeyEventArgs)

Overridden to set the starting point and length of the text selected and set the text in the Text box.

Declaration
protected override void OnKeyDown(KeyEventArgs e)
Parameters
Type Name Description
System.Windows.Forms.KeyEventArgs e
Overrides

OnKeyPress(KeyPressEventArgs)

Invoked when user pressed key.

Declaration
protected override void OnKeyPress(KeyPressEventArgs e)
Parameters
Type Name Description
System.Windows.Forms.KeyPressEventArgs e

A System.Windows.Form.KeyEventArgs with data of the keyboard event.
Overrides

OnPrepareViewStyleInfo(GridPrepareViewStyleInfoEventArgs)

Allows custom formatting of a cell by changing its style object.

Declaration
public override void OnPrepareViewStyleInfo(GridPrepareViewStyleInfoEventArgs e)
Parameters
Type Name Description
GridPrepareViewStyleInfoEventArgs e

An System.EventARgsthat contains the event data.
Overrides

OnRejectChanges()

Overridden to get the GridStyleInfo of the cells and sets the list box part text.

Declaration
protected override void OnRejectChanges()
Overrides

OnSetControlText(String)

Overridden to sets the control text to the list box part.

Declaration
protected override void OnSetControlText(string text)
Parameters
Type Name Description
System.String text
Overrides

ProcessMouseWheel(MouseEventArgs)

Allows the cell renderer to process the mouse wheel.

Declaration
public override bool ProcessMouseWheel(MouseEventArgs e)
Parameters
Type Name Description
System.Windows.Forms.MouseEventArgs e

A System.Windows.Form.MouseEventArgs holding the event data.
Returns
Type Description
System.Boolean

True if the popup child is dropped down and the new scroll position is valid.
Overrides

SynchronizeDisplayText(Int32)

Retrieves the text from the list box index and sets the TextBoxText. Called when the user presses arrow keys to move selection in dropped list box.

Declaration
protected virtual void SynchronizeDisplayText(int index)
Parameters
Type Name Description
System.Int32 index

The list box index

TextBoxChanged(Object, EventArgs)

Occurs when the System.Windows.Forms.Control.TextChanged event of the TextBox is raised.

Declaration
protected override void TextBoxChanged(object sender, EventArgs e)
Parameters
Type Name Description
System.Object sender

The source of the event.
System.EventArgs e

An System.EventArgsthat contains event data.
Overrides

ValidateString(String)

Checks if the specified text is valid.

Declaration
public override bool ValidateString(string text)
Parameters
Type Name Description
System.String text

The specified text.
Returns
Type Description
System.Boolean

True if it is valid.
Overrides

Implements

System.IDisposable