Sharepoint开发中很多时候都需要你自定义一个field type,只有这样才能满足我们的自定义的需求，并且实现我们对UI的定制，达到我们对其扩展的目的
1. 编写一个xml文件用来描述这个自定义的field type的属性（文件名字需要以fldtypes开头，例如：fldtypes_testfieldtype.xml）
2. 编写一个自定义控件（UserControl，例如：TestFieldEditor.ascx），用来在使用这个field type创建column的时候添加一些这种field type所需要的配置数据，例如：一个lookup field需要添加一个List和一个这个List下的column作为这个lookup的数据源。
3. 编写一个sharepoint template,作为这个field type的控件的template,实现定制UI
4. 重写一个sharepoint field type作为这个自定义的field type的基类
5. 重写sharepoint basefieldcontrol作为这个自定义field type的control
Fldtypes_testfieldtype.xml如下：
<?xml version="1.0" encoding="utf-8" ?>
<FieldTypes>
<FieldType>
<Field Name="TypeName">ExLookField</Field>
<Field Name="TypeDisplayName">ExLookField </Field>
<Field Name="TypeShortDescription">Extesion of lookup field </Field>
<Field Name="TypeDescription">This column allows for…..</Field>
<Field Name="ParentType">Lookup</Field>
<Field Name="FieldEditorUserControl">/_controltemplates/TestFieldEditor.ascx</Field>
<Field Name="FieldTypeClass">
TestField,
TestField,
Version=1.0.0.0,
Culture=neutral,
PublicKeyToken=8ce44e7ccb44bd10</Field>
<RenderPattern Name="DisplayPattern">
<LookupColumn HTMLEncode="TRUE" AutoHyperLink="FALSE" />
</RenderPattern>
</FieldType>
</FieldTypes>
TestFieldEditor.ascx代码如下：
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="TestFieldEditor.ascx.cs" Inherits="TestFieldEditor, TestFields, Version=1.0.0.0, Culture=neutral, PublicKeyToken=8ce44e7ccb44bd10" %>
<%@ Register TagPrefix="wssuc" TagName="InputFormControl" src="~/_controltemplates/InputFormControl.ascx" %>
<%@ Register TagPrefix="wssuc" TagName="InputFormSection" src="~/_controltemplates/InputFormSection.ascx" %>
<%@ Register Tagprefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register Tagprefix="Utilities" Namespace="Microsoft.SharePoint.Utilities" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Import Namespace="Microsoft.SharePoint" %>
<wssuc:InputFormSection runat="server" id="TestSections" Title="Special Configuration Section">
<Template_InputFormControls>
<wssuc:InputFormControl runat="server"
LabelText="Test。。。。">
<Template_Control>
<sharepoint:PeopleEditor ID="AllowedPrincipalsPeoplePicker" runat="server" AutoPostBack="false" PlaceButtonsUnderEntityEditor="true" SelectionSet="SPGroup" MultiSelect="true" />
<asp:Button runat="server" Text="TestButton"/>
</Template_Control>
</wssuc:InputFormControl>
</Template_InputFormControls>
</wssuc:InputFormSection>
自定义sharepoint template 如下：
<%@ Control Language="C#" %>
<%@ Assembly Name="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register TagPrefix="SharePoint" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c"
Namespace="Microsoft.SharePoint.WebControls" %>
<SharePoint:RenderingTemplate ID="TestLookupFieldControl" runat="server">
<Template>
<asp:TextBox ID="TbTest" runat="server"></asp:TextBox>
<asp:ImageButton ID="IBTest" runat="server" />
<asp:Button ID="BtnTest" runat="server" />
</Template>
</SharePoint:RenderingTemplate>
自定义的field type（继承SPFieldLookup）,代码如下：
public class ExLookupField : SPFieldLookup
{
publicExLookupField(SPFieldCollection fields, string fieldName)
: base(fields, fieldName) { }
public ExLookupField(SPFieldCollection fields, string typeName, string displayName)
: base(fields, typeName, displayName) { }
public override Microsoft.SharePoint.WebControls.BaseFieldControl FieldRenderingControl
{
get
{
BaseFieldControl control = new TestLookupControl();
control.FieldName = this.InternalName;
return control;
}
}
public override string GetValidatedString(object value)
{
if (value == null)
{
throw new SPFieldValidationException("value is null.");
}
return string.Empty;
}
}
编写一个自定义的control(继承BaseFieldControl)其实现如下：
public class LookupControl : BaseFieldControl
{
protected TextBox mCompanySizeSelector;
protected ImageButton mImage;
protected Button mButton;
protected override string DefaultTemplateName
{
get
{
return @"TestLookupFieldControl";
}
}
public override object Value
{
get
{
Return ;
}
set
{
}
}
protected override void CreateChildControls()
{
base.CreateChildControls();
}
以上就是对自定义field type的开发的整个流程的介绍，并且对需要的文件做详细的介绍，可以在相应的文件中添加自己的code实现自定义的逻辑，
完成所需要的功能。