Creating Custom Field Types in SharePoint using Visual Studio

Here we are planning to create a Custom field will auto populate with the logged in user information. First we need create project with SharePoint assembly as reference. For this create empty SharePoint Application project.
> Start Visual Studio.
> On the File menu, click New, and then click Project.
> In the Project Types pane of the New Project dialog box, select Visual C#, and then select the SharePoint category.
>In the Templates pane, click Empty. Specify a Name and Location for the project, and then click OK. Visual Studio creates a solution that contains an empty project.

Visual Studio Extensions for Windows SharePoint Services 3.0 provides support
for creating SharePoint field types through the Field Control project item.

Now we need to add a Field Control to the Project we have created.

> In the Visual Studio Solution Explorer, right-click the empty project created in the previous procedure, click Add, and then click New Item.
> In the Categories pane of the Add New Item dialog box, expand the Visual C# Project Items node, and then select the SharePoint category.
> In the Templates pane, click Field Control. Specify LoginInfoID for the Name of the field control, and then click Add. Visual Studio adds the new field control to the project.

Visual Studio adds two Microsoft Visual C# code files to the project: LoginInfoID.FieldControl.cs and LoginInfoID.Field.cs. The LogoField.Field.cs file contains code that defines a class that by default is derived from the SPFieldText class and that overrides the FieldRenderingControl property.

Now write the custom logic inside the LoginInfoID.FieldControl.cs file. Refer the this full source attached in this blog for understand the remaining. Download Source Code

Now the field control xml file and deployment.

The XML file must be named in the format fldtypes*.xml (for example, fldtypes_customfield.xml) and placed in Local_Drive:\\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\XML
Upload all the .dll files into the Drive:\WINDOWS\assembly folder
At a command prompt, type iisreset to reset Internet Information Services (IIS).
In a view of the list to which you want to add the custom field type, click Settings, and then click Create Column.

Result as shown screenshot