Question

I’ve created a contentype that inherits from the item contenttype. So the contenttype automaticaly has the field: Title.

But how access this field (I want to add some custom validation and define if it is shown in editform)?

I want to do serverside validation and use the custom edititemform. Perhabs there is a possibility to delete/hide this field?

I’ve tried to change the content type to hide the title:

 <Field
  ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}"
  Name="Title"
  StaticName="Title"
  DisplayName="Title"
  Type="Text"
  FromBaseType="TRUE"
  Required="FALSE"
  Hidden="TRUE"
  SourceID="http://schemas.microsoft.com/sharepoint/v3"
/>



  <!-- Parent ContentType: Element (0x01) -->
  <ContentType ID="0x0100b48c62c42879472aa8f1e1afc4dba7ce"
               Name="aa- aa"               
               Group="Custom Content Types"
               Description="My Content Type"
               Inherits="TRUE"
               Version="0">
      <FieldRefs>
        <FieldRef ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}" Name="Title" Hidden="TRUE" Required="FALSE" />

      </FieldRefs>

But the title field is still required and shown.

Answer 1

I found the problem:

If I want to hide to remove the title collumn in my contenttype I have to disable the contenttypes inharitation. But after disabeling the inharitation the custom collumns will disapear after deployment. Because they are not part of the base type. SO the fields have to be declared in the list schema too.

MSDN

When SharePoint Foundation creates a list instance, it includes only
those columns that are declared in the base type schema of the list or
in the list schema. If you reference a site content type in the list
schema, and that content type references site columns that are not
included in the base type schema of the list or in the list schema,
those columns are not included. You must declare those columns in the
list schema for SharePoint Foundation to include them on the list.

Contenttype

<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Field ID="{61CC6776-F855-48d5-A4EC-B7CE11CE2324}"
      DisplayName="ExpiresDate" Name="ExpiresDate"
      Type="DateTime" Required="False"
      UnlimitedLengthInDocumentLibrary="FALSE"/>


  <!-- Parent ContentType: Element (0x01) -->
  <ContentType ID="0x0100b48c62c42879472aa8f1e1afc4dba7ce"
               Name="GroupsList - ContentTypeGroups"               
               Group="Custom Content Types"
               Description="My Content Type"
               Inherits="false"
               Version="0">
      <FieldRefs>
        <RemoveFieldRef ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}" />

      <FieldRef ID="{61CC6776-F855-48d5-A4EC-B7CE11CE2324}" Name="ExpiresDate" Required="FALSE" ShowInNewForm="FALSE" ShowInEditForm="FALSE" />
      </FieldRefs>
  </ContentType>
</Elements>

List Schema

...

  <ContentTypes>

      <ContentTypeRef ID="0x0100b48c62c42879472aa8f1e1afc4dba7ce" />
    </ContentTypes>
    <Fields>
      <Field ID="{61CC6776-F855-48d5-A4EC-B7CE11CE2324}"
          DisplayName="ExpiresDate" Name="ExpiresDate"
          Type="DateTime" Required="False"
          UnlimitedLengthInDocumentLibrary="FALSE"/>

    </Fields>
...