最近谈论较多的就是datagrid,特别新手最是郁闷为何没有更好的控件,来满足自已的需求。
其实通过重写可以达到很多不同的功能体验,在这里我们仅仅讨论关于datagridcolumnstyle重写的问题
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1。重写textbox：
public class xp_textbox
inherits system.windows.forms.textbox
#region " windows "
public sub new()
mybase.new()
initializecomp
end sub
protected overloads overrides sub dispose(byval disposing as boolean)
if disposing then
if not (comp is nothing) then
components.dispose()
end if
end if
mybase.dispose(disposing)
end sub
'windows
private comp as system.componentmodel.ic
<system.diagnostics.debuggerstepthrough()> private sub initializecomp
'
'textbox
'
me.enablec = true
me.enablepaste = true
me.name = "textbox"
end sub
#end region
#region " variables "
private m_enpaste as boolean = true
private m_enc as boolean = true
#end region
#region " property "
property enablepaste() as boolean
get
return m_enpaste
end get
set(byval value as boolean)
m_enpaste = value
me.invalidate()
end set
end property
property enablec as boolean
get
return m_enc
end get
set(byval value as boolean)
m_enc = value
me.invalidate()
end set
end property
#end region
protected overrides sub wndproc(byref m as system.windows.forms.message)
select case m.msg
case &h302 'paste
raiseevent pasteevent()
if not m_enpaste then return
case &h7b 'c
if not m_enc then return
end select
mybase.wndproc(m)
end sub
public event pasteevent()
end class
2。重写datagridcolumnstyle(重点介绍内容)：
imports system.drawing
imports system.windows.forms
public notinheritable class datagridtextboxcolumnstyle
inherits system.windows.forms.datagridcolumnstyle
#region "declare property"
private withevents m_textbox as new landlord.component.xp_textbox
private isediting as boolean
private editingrow as integer = -1
private m_oldvalue as string
#end region
#region " windows "
sub new()
me.m_textbox.visible = false
end sub
public sub new(byval c as system.componentmodel.ic
myclass.new()
container.add(me)
end sub
protected overloads overrides sub dispose(byval disposing as boolean)
if disposing then
if not (comp is nothing) then
components.dispose()
end if
end if
mybase.dispose(disposing)
end sub
private comp as system.componentmodel.ic
<system.diagnostics.debuggerstepthrough()> private sub initializecomp
comp = new system.componentmodel.c
end sub
#end region
#region "get functi
protected overrides function getminimumheight() as integer
return m_textbox.preferredheight + 2
end function
protected overrides function getpreferredheight(byval g as system.drawing.graphics, byval value as object) as integer
return m_textbox.preferredheight + 2
end function
protected overrides function getpreferredsize(byval g as system.drawing.graphics, byval value as object) as system.drawing.size
return new size(50, m_textbox.preferredheight + 2)
end function
#end region
#region "paint"
protected overloads overrides sub paint(byval g as system.drawing.graphics, byval bounds as system.drawing.rectangle, byval [source] as system.windows.forms.currencymanager, byval rownum as integer)
paint(g, bounds, [source], rownum, false)
end sub
protected overloads overrides sub paint(byval g as system.drawing.graphics, byval bounds as system.drawing.rectangle, byval [source] as system.windows.forms.currencymanager, byval rownum as integer, byval aligntoright as boolean)
dim brush_for as brush = new solidbrush(me.datagridtablestyle.forecolor)
dim brush_bak as brush = new solidbrush(me.datagridtablestyle.backcolor)
paint(g, bounds, [source], rownum, brush_bak, brush_for, aligntoright)
brush_for.dispose()
brush_bak.dispose()
end sub
protected overloads overrides sub paint(byval g as system.drawing.graphics, byval bounds as system.drawing.rectangle, byval [source] as system.windows.forms.currencymanager, byval rownum as integer, byval backbrush as brush, byval forebrush as brush, byval aligntoright as boolean)
dim str as string
if isdbnull(getcolumnvalueatrow([source], rownum)) then
str = me.nulltext
else
str = ctype(getcolumnvalueatrow([source], rownum), string)
end if
dim brush as brush = backbrush
dim rect as system.drawing.rectangle = bounds
g.fillrectangle(brush, rect)
if me.isediting and editingrow = rownum then
brush = new solidbrush(color.white)
g.fillrectangle(brush, bounds)
end if
rect.offset(0, 2)
rect.height -= 2
brush = new solidbrush(me.datagridtablestyle.forecolor)
if me.datagridtablestyle.datagrid.isselected(rownum) then
brush = new solidbrush(me.datagridtablestyle.selecti
dim rectf as rectanglef = new rectanglef(bounds.x, bounds.y, bounds.width, bounds.height)
g.fillrectangle(brush, rectf)
brush = new solidbrush(me.datagridtablestyle.selecti
end if
if me.alignment = horizontalalignment.center then
dim w as integer = g.measurestring(str, me.datagridtablestyle.datagrid.f new sizef(bounds.width, bounds.height)).width
rect.x = rect.x + (bounds.width – w) / 2
elseif me.alignment = horizontalalignment.right then
dim w as integer = g.measurestring(str, me.datagridtablestyle.datagrid.f new sizef(bounds.width, bounds.height)).width
rect.x = bounds.right – w
end if
g.drawstring(str, me.datagridtablestyle.datagrid.f brush, rect.x, rect.y)
brush.dispose()
end sub
#end region
#region "overrides method"
protected overrides function commit(byval datasource as system.windows.forms.currencymanager, byval rownum as integer) as boolean
me.m_textbox.bounds = rectangle.empty
if not me.isediting then
return true
end if
editingrow = -1
isediting = false
try
dim value as object
value = m_textbox.text
if nulltext.equals(value) then
value = system.dbnull.value
end if
setcolumnvalueatrow(datasource, rownum, value)
catch ex as exception
abort(rownum)
return false
end try
invalidate()
return true
end function
protected overrides sub abort(byval rownum as integer)
me.m_textbox.text = m_oldvalue
editingrow = -1
if m_textbox.focused then
me.datagridtablestyle.datagrid.focus()
end if
me.m_textbox.visible = false
me.isediting = false
me.invalidate()
end sub
protected overloads overrides sub edit(byval source as system.windows.forms.currencymanager, byval rownum as integer, byval bounds as system.drawing.rectangle, byval [readonly] as boolean, byval instanttext as string, byval cellisvisible as boolean)
editingrow = rownum
isediting = true
dim value as string
if isdbnull(getcolumnvalueatrow(source, rownum)) then
value = me.nulltext
else
value = ctype(getcolumnvalueatrow(source, rownum), string)
end if
m_oldvalue = value
if cellisvisible then
if not me.readonly then
me.m_textbox.bounds = new rectangle(bounds.x + 1, bounds.y + 1, bounds.width – 2, bounds.height – 2)
me.m_textbox.text = value
me.m_textbox.select()
me.m_textbox.focus()
me.m_textbox.selectall()
me.m_textbox.visible = true
me.m_textbox.flat = true
end if
else
me.m_textbox.text = value
'滚动时会丢失焦点
'me.m_textbox.visible = false
end if
if me.m_textbox.visible then
datagridtablestyle.datagrid.invalidate(bounds)
end if
end sub
protected overloads overrides sub setdatagridincolumn(byval value as system.windows.forms.datagrid)
mybase.setdatagridincolumn(value)
if not m_textbox.parent is nothing then
m_textbox.parent.controls.remove(me.m_textbox)
end if
if not value is nothing then
value.controls.add(me.m_textbox)
end if
end sub
protected overrides sub c
editingrow = -1
'否则先点到新增行,再回选非新行格时该列最后一行的值变为(null)
isediting = false
me.m_textbox.visible = false
invalidate()
end sub
protected overrides sub enternullvalue()
me.m_textbox.text = me.nulltext
end sub
private sub m_textbox_keypress(byval sender as object, byval e as system.windows.forms.keypresseventargs) handles m_textbox.keypress
if not char.iscontrol(e.keychar) then
me.isediting = true
mybase.columnstartedediting(m_textbox)
end if
end sub
private sub m_textbox_pasteevent() handles m_textbox.pasteevent
me.isediting = true
me.columnstartedediting(m_textbox)
end sub
#end region
end class
3。使用：
新建一个空窗体,拖入datagrid,窗体load事件中代码如下
private idtb_temp as new datatable
private sub form1_load(byval sender as system.object, byval e as system.eventargs) handles mybase.load
idtb_temp = new datatable("nametable")
idtb_temp.columns.add(new datacolumn("normal"))
idtb_temp.columns.add(new datacolumn("textbox1"))
idtb_temp.columns.add(new datacolumn("combobox1"))
dim datecolumns as datacolumn
datecolumns = new datacolumn("datetime1", type.gettype("system.datetime"))
idtb_temp.columns.add(datecolumns)
idtb_temp.columns.add(new datacolumn("checkbox1", type.gettype("system.boolean")))
dim idrw_row as datarow
dim i as integer
for i = 0 to 20
idrw_row = idtb_temp.newrow
idrw_row.item("normal") = "names"
idrw_row.item("textbox1") = "nick"
idrw_row.item("combobox1") = i.tostring
idrw_row.item("datetime1") = "2004-06-04"
idrw_row.item("checkbox1") = true
idtb_temp.rows.add(idrw_row)
next
me.datagrid1.datasource = idtb_temp
dim mygridstyle as windows.forms.datagridtablestyle = new windows.forms.datagridtablestyle
mygridstyle.mappingname = "nametable"
mygridstyle.preferredrowheight = 30
mygridstyle.selecti = color.blue
mygridstyle.backcolor = color.yellow
dim c1 as windows.forms.datagridtextboxcolumn = new windows.forms.datagridtextboxcolumn
with c1
.mappingname = "normal"
.width = 100
.headertext = "normal"
.alignment = horizontalalignment.center
end with
mygridstyle.gridcolumnstyles.add(c1)
dim c2 as landlord.component.draggrid.datagridtextboxcolumnstyle = new landlord.component.draggrid.datagridtextboxcolumnstyle
with c2
.mappingname = "textbox1"
.width = 100
.headertext = "textbox1"
end with
mygridstyle.gridcolumnstyles.add(c2)
dim c3 as landlord.component.draggrid.datagridcomboboxcolumnstyle = new landlord.component.draggrid.datagridcomboboxcolumnstyle
with c3
.mappingname = "combobox1"
.headertext = "combobox1"
.width = 100
.additem("111")
.additem("222")
.alignment = horizontalalignment.center
end with
mygridstyle.gridcolumnstyles.add(c3)
dim c4 as landlord.component.draggrid.datagriddatetimepickercolumnstyle = new landlord.component.draggrid.datagriddatetimepickercolumnstyle
with c4
.mappingname = "datetime1"
.headertext = "datetime1"
.width = "100"
.alignment = horizontalalignment.center
end with
mygridstyle.gridcolumnstyles.add(c4)
dim c5 as landlord.component.draggrid.datagridcheckboxcolumnstyle = new landlord.component.draggrid.datagridcheckboxcolumnstyle
with c5
.mappingname = "checkbox1"
.headertext = "checkbox1"
.width = 100
.truecolor = color.red
end with
mygridstyle.gridcolumnstyles.add(c5)
me.datagrid1.tablestyles.clear()
me.datagrid1.tablestyles.add(mygridstyle)
end sub
4。说明：
其他控件的加入原理基本一样,这里就不重复了