ReoGrid Forum

gnetz

Member

Registered: 2015-02-11

Posts: 7

DropDownListCell for entire column.

Dim x As New DropdownListCell
x.Items.Add("aaaa1")
x.Items.Add("aaaa2")
x.Items.Add("aaaa3")

Grid.CurrentWorksheet.ColumnHeaders("B").DefaultCellBody = GetType(unvell.ReoGrid.CellTypes.DropdownListCell())

Grid.CurrentWorksheet.SetCellData("B", x)

DropDownListCell created successfully, but DropDownListCell Items not added to all the rows.

Jingwood

Moderator

From: jing at reogrid.net

Registered: 2014-06-03

Posts: 615

Re: DropDownListCell for entire column.

How many rows on your worksheet?

Last edited by Jingwood (2015-02-11 09:29:31)

gnetz

Member

Registered: 2015-02-11

Posts: 7

Re: DropDownListCell for entire column.

5000 rows sir,

Jingwood

Moderator

From: jing at reogrid.net

Registered: 2014-06-03

Posts: 615

Re: DropDownListCell for entire column.

OK since the default built-in DropdownListCell will create one ListBox instance for one cell, it will be many ListBox control instances in memory if you have so many rows. Below is a solution that the ColumnDropdownListCell class only create one ListBox control instance in memory and it will be commonly used for all cells on entire column.

Class ColumnDropdownListCell: (VB.NET)

Class ColumnDropdownListCell
	Inherits DropdownCell

	' Create only one listbox instance that is commonly used for entire column
	Shared listbox As New ListBox With {
		.BorderStyle = Windows.Forms.BorderStyle.None
	}

	Shared Sub New()
		' Initialize listbox items
		listbox.Items.AddRange({"A", "B", "C"})
	End Sub

	Sub New()
		' When cell body instance created, set listbox as dropdown control
		MyBase.DropdownControl = listbox
	End Sub

	Public Overrides Sub PushDown()
		' Add event listener when got focus
		AddHandler listbox.Click, AddressOf ListBox_Click
		MyBase.PushDown()
	End Sub

	Sub ListBox_Click(s As Object, e As EventArgs)
		' Choose listbox item, set to cell as data
		MyBase.Cell.Data = listbox.SelectedItem

		' Remove event listener when lost focus
		RemoveHandler listbox.Click, AddressOf ListBox_Click

		' Close dropdown panel
		MyBase.PullUp()
	End Sub

End Class

Use it:

' Set default body type
Me.worksheet.ColumnHeaders("B").DefaultCellBody = GetType(ColumnDropdownListCell)

' Initialize dummy data
Me.worksheet("B1:B9") = {"A", "B", "C", "A", "B", "C", "A", "B", "C"}

gnetz

Member

Registered: 2015-02-11

Posts: 7

Re: DropDownListCell for entire column.

Thank you sir,
It is working.....