完全用编码实现gridview创建和clounms的添加.docx

完全用编码实现gridview创建和clounms的添加.docx

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完全用编码实现gridview创建和clounms的添加

完全用编码实现gridview创建和clounms的添加。

Part1

protectedvoidPage_Load（objectsender,EventArgse）

{

SqlDataSource1.ConnectionString=

@"datasource=.;initialcatalog=northwind;integratedsecurity=true";

SqlDataSource1.SelectCommand=

"selectemployeeID,FirstName,LastNamefromemployees";

SqlDataSource1.UpdateCommand=

"updateemployeessetfirstname=@FirstName,lastname=@LastNamewhereemployeeid=@EmployeeID";

SqlDataSource1.UpdateParameters.Add（"@FirstName",""）;

SqlDataSource1.UpdateParameters.Add（"@LastName",""）;

SqlDataSource1.UpdateParameters.Add（"@EmployeeID",""）;

if（!

IsPostBack）

{

GridView1.DataSourceID="SqlDataSource1";

GridView1.AutoGenerateColumns=false;

GridView1.DataKeyNames=newstring[]{"EmployeeID"};

GridView1.AllowPaging=true;

GridView1.AllowSorting=true;

GridView1.PageSize=5;

BoundFieldbf1=newBoundField（）;

BoundFieldbf2=newBoundField（）;

BoundFieldbf3=newBoundField（）;

bf1.HeaderText="EmployeeID";

bf1.DataField="EmployeeID";

bf1.ReadOnly=true;

bf1.SortExpression="EmployeeID";

bf2.HeaderText="FirstName";

bf2.DataField="FirstName";

bf2.SortExpression="FirstName";

bf3.HeaderText="LastName";

bf3.DataField="LastName";

bf3.SortExpression="LastName";

CommandFieldcf=newCommandField（）;

cf.ButtonType=ButtonType.Button;

cf.ShowCancelButton=true;

cf.ShowEditButton=true;

GridView1.Columns.Add（bf1）;

GridView1.Columns.Add（bf2）;

GridView1.Columns.Add（bf3）;

GridView1.Columns.Add（cf）;

}

}

完全用编码实现gridview创建和clounms的添加。

Part2

Introduction

InPart1 youlearnedtocreateBoundFieldsandCommandFieldsdynamically.Oftenyourgridlayoutisbeyondthecapabilitiesofin-builtcolumntypesandyouneedtouseTemplateFields.Forexample,let'ssayyouarecreatingaproductcatalog. Certainlynormal tabularlayoutisnotsuitablehereasyouwanttodisplayeachrecordinahighlycustomizedformat.Templatefieldscancomehandyinsuchsituations.InthisarticleIamgoingtoillustratehowtemplatefieldscanbeaddeddynamically.Youwilllearntwotechniquesofdoingso:

∙UsingLoadTemplate（）method

∙Bycreatingacustomtemplateclass

AddingTemplateFieldsUsingLoadTemplate（）Method

InordertoworkwiththisexampleyouneedtocreateanewwebsiteinVisualStudio.DraganddropaGridViewonthedefaultpage.AlsodraganddropanSqlDataSourcecontrol.Wewillbesettingvariouspropertiesofthesecontrolsviacode.InthefirstmethodofaddingtemplatefieldswewillbeusingLoadTemplate（）method.TheLoadTemplate（）methodisavailabletoalltemplatecontrolsincludingthePage.Itaccepts virtualpathofafileandloadsthetemplatespecifiedtherein.ThereturnvalueofLoadTemplate（）isanobjectthatimplementsITemplateinterface.

InourexamplewewillcreatethetemplateinaUserControl.Todoso,addanewWebUserControltothewebsiteandnameitasItemTemplate.ascx.Keyinthefollowingmarkuptoit.

<%@ControlLanguage="C#"AutoEventWireup="true"

CodeFile="ItemTemplate.ascx.cs"Inherits="ItemTemplate"%>

LabelID="Label1"runat="server"

Text='<%#Eval（"EmployeeID"）%>'>

Label>

LabelID="Label2"runat="server"

Text='<%#Eval（"FirstName"）%>'>

Label>

LabelID="Label3"runat="server"

Text='<%#Eval（"LastName"）%>'>

Label>

Noticeabovemarkupcarefully.ItcontainsthreeLabelcontrols.TheTextpropertyofeachLabelisboundwithEmployeeID,FirstNameandLastNamecolumnsofEmployeestablerespectively.TheEval（）expressionisonewaydatabindingexpressionofASP.NETandacceptsthenameofthecolumntobind.ThisusercontrolwillactasourItemTemplatelater.

NowopenthecodebehindfileofthedefaultwebformandkeyinthefollowingcodeinPage_Loadeventhandler.

protectedvoidPage_Load（objectsender,EventArgse）

{

SqlDataSource1.ConnectionString=

@"datasource=.;initialcatalog=northwind;integratedsecurity=true";

SqlDataSource1.SelectCommand=

"selectemployeeID,FirstName,LastNamefromemployees";

if（!

IsPostBack）

{

GridView1.DataSourceID="SqlDataSource1";

GridView1.AutoGenerateColumns=false;

TemplateFieldtf1=newTemplateField（）;

tf1.ItemTemplate=LoadTemplate（"ItemTemplate.ascx"）;

GridView1.Columns.Add（tf1）;

}

}

Thecode pointstheConnectionStringpropertyofSQLdatasourcecontroltoNorthwinddatabase.TheSelectCommandpropertyspecifiesaSELECTstatementthatfetchesEmployeeID,FirstNameandLastNamecolumnsofEmployeestable.Next,itsetsDataSourceIDpropertyofGridViewcontroltotheIDofSQLDataSourcecontrol.Also,AutoGenerateColumnspropertyissettofalseaswewillbeaddingcolumnsprogrammatically.Nextfewlinesareimportant.ThecodethencreatesaninstanceofTemplateFieldclass.TheTemplateFieldclassrepresentsatemplatecolumnofGridViewclass.TheItemTemplatepropertyofTemplateFieldclassisthensettothereturnvalueofLoadTemplate（）method.TheLoadTemplate（）methodacceptsavirtualpathofthefilecontainingtemplatetobeloaded（ItemTemplate.ascxinourcase）.TheTemplateFieldisthenaddedtotheColumnscollectionofGridViewcontrol.

Runthewebformandyourbrowsershoulddisplaysomethingasshownbelow:

Noticehowthetemplatespecifiedintheusercontrolisapplied.Also,noticethatheaderisshownblankbecausewedidnotspecifiedHeaderTemplate.Youcaneitherspecifyitorturntheheaderoff.

AddingTemplateFieldUsingCustomTemplateClass

NowthatyouknowhowtouseLoadTemplate（）methodlet'smovetoanotherpossibility.YoulearntinthelastexamplethatLoadTemplate（）methodreturnsanobjectthatimplementsITemplateinterface.YouyourselfcancreatesuchaclassanduseitdirectlyinyourcodeinsteadofusingLoadTemplate（）method.

TobeginwithaddanewclassnamedMyTemplatetoApp_Codefolder.KeyinthefollowingcodetoMyTemplateclass.

publicclassMyTemplate:

ITemplate

{

privatestringcolname;

publicMyTemplate（stringcolname）

{

this.colname=colname;

}

publicvoidInstantiateIn（Controlcontainer）

{

LiteralControll=newLiteralControl（）;

l.DataBinding+=newEventHandler（this.OnDataBinding）;

container.Controls.Add（l）;

}

publicvoidOnDataBinding（objectsender,EventArgse）

{

LiteralControll=（LiteralControl）sender;

GridViewRowcontainer=（GridViewRow）l.NamingContainer;

l.Text=（（DataRowView）container.DataItem）[colname].ToString（）;

}

}

ThecodecreatesaclasscalledMyTemplatethatimplementsITemplateinterface.TheITemplateinterfacecontainsasinglemethod-InstantiateIn（）-thatyoumustimplement.Thecodethendeclaresastringvariabletoholdacolumnnametobedisplayed.Thecolumnnameissetintheconstructoroftheclass.ThenInstantiateIn（）methodisimplemented.ThemethodreceivesanobjectoftypeControlthatrepresentscontainerorparentcontrol.InsidewecreateaLiteralControlandattachaneventhandler（OnDataBinding）toitsDataBindingevent.ThiseventisraisedwhenthecontainercontrolcallsDataBind（）methodonitself.TheLiteralControlisthenaddedtotheControlscollectionofthecontainercontrol.

TheOnDataBinding（）eventhandlerdoesthejobofdatabindingtheLiteralControlwiththerequireddata.ItthengetsareferencetotherowinwhichthecontrolisbeingaddedusingNamingContainerproperty.Finally,TextpropertyofLiteralControlissettothevalueofdatabasecolumnasspecifiedintheconstructor.Thiscompletesourcustomtemplateclass.

Nowaddanewwebformtothesamewebsite.DraganddropaGridViewandSqlDataSourcecontrolasbefore.AddthefollowingcodeinthePage_Loadeventhandleroftheform.

protectedvoidPage_Load（objectsender,EventArgse）

{

SqlDataSource1.ConnectionString=

@"datasource=.;initialcatalog=northwind;integratedsecurity=true";

SqlDataSource1.SelectCommand=

"selectemployeeID,FirstName,LastNamefromemployees";

if（!

IsPostBack）

{

GridView1.DataSourceID="SqlDataSource1";

GridView1.AutoGenerateColumns=false;

TemplateFieldtf1=newTemplateField（）;

MyTemplatet1=newMyTemplate（"FirstName"）;

tf1.HeaderText="FirstName";

tf1.ItemTemplate=t1;

TemplateFieldtf2=newTemplateField（）;

MyTemplatet2=newMyTemplate（"LastName"）;

tf2.HeaderText="LastName";

tf2.ItemTemplate=t2;

GridView1.Columns.Add（tf1）;

GridView1.Columns.Add（tf2）;

}

}

ThecodesetsthepropertiesofSqlDataSourceandGridViewasbefore.Noticethecodemarkedinboldletters.ThecodecreatesaninstanceofTemplateFieldclassasbefore.ThistimetheItemTemplatepropertyofTemplateFieldissettoanewinstanceofMyTemplateclass.Thecolumnnames-FirstNameandLastName-arepassedintheconstructor.Finally,thetemplatefieldsareaddedtotheColumnscollectionofGridViewclass.

Thefollowingscreenshotshowsasamplerunoftheabove webform.

That'sit!

Happycoding.