How to manage column-based access control in Sharepoint lists?

Question

I am making a sharepoint based problem tracking portal. Users should be able to add entries, but in the entry itself, I want one column to be visible only to a specific group of users (administrators). Is there a way to set column-based access control?

Answer 1

As far as I know, it is not available on the standard platform. What you can do, on the other hand, is to use your own field control

So in custom fieldtypes.xml

<FieldTypes>

  <FieldType>
    <Field Name="TypeName">MyInteger</Field>
    <Field Name="ParentType">Integer</Field>
    ...
    <Field Name="FieldTypeClass">xxx</Field>
  </FieldType>

and in sitecolumns.xml

  <Field ID="xxx"
      Name="xxx"
      DisplayName="xxx
      Description="xxx"
      Group="xxx
      Type="MyInteger"    
      DisplaceOnUpgrade="TRUE"
  />

and in your field office

public class MyInteger: SPFieldNumber
{
    public MyInteger(SPFieldCollection fields, string fieldName)
        : base(fields, fieldName)
    {
    }

    public MyInteger(SPFieldCollection fields, string typeName, string displayName)
        : base(fields, typeName, displayName)
    {
    }


    public override BaseFieldControl FieldRenderingControl
    {
        [SharePointPermission(SecurityAction.LinkDemand, ObjectModel = true)]
        get
        {
            Microsoft.SharePoint.WebControls.BaseFieldControl ctl = 
               new MyIntegerControl();
            ctl.FieldName = InternalName;
            return ctl;

        }
    }

    }

and in MyIntegerControl you can do whatever you want (many overrides), but an example:

protected override void CreateChildControls()
{
    base.CreateChildControls();
    if (this.ControlMode == SPControlMode.New || 
        this.ControlMode == SPControlMode.Display)
    {
      // check that use is admin and display value
    }
}

Answer 2

, CustomAction,

     <CustomAction Id="CustomAction"
          GroupId="SiteActions"
          Location="Microsoft.SharePoint.StandardMenu"
          Sequence="1003"
          ControlAssembly="$SharePoint.Project.AssemblyFullName$"
       ControlClass="CustomAction.ColumnPermissionAction"/>

:

class ColumnPermissionAction : Control
{
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        HideColumn();
    }

    private HideColumn(){
         WebPart part=//find your web part
         string colName="SecretColumn";
         if(part is ListViewWebPart){
            (part as ListViewWebPart).ListViewXml = (part as ListViewWebPart).ListViewXml.Replace(string.Format("<FieldRef Name=\"{0}\"/>", colName), string.Empty);
         }else if(part is XsltListViewWebPart){
            PropertyInfo property = typeof(DataFormWebPart).GetProperty("ListViewXmlDom", BindingFlags.NonPublic | BindingFlags.Instance);
            if (property != null)
            {
                XmlNode xmlView = property.GetValue(part as XsltListViewWebPart, null) as XmlNode;
                if (xmlView != null)
                {
                    XmlNode node = xmlView.SelectSingleNode("//ViewFields");
                    if (node != null)
                    {
                            var field = node.SelectSingleNode(string.Format("FieldRef[@Name='{0}']", colName));
                            if (field != null)
                            {
                                node.RemoveChild(field);
                            }
                    }
                }
            }
         }
    }
}