public SPField TryGetField(SPFieldCollection siteColumns, Guid fieldID)
{
siteColumns.RequireNotNull("siteColumns");
fieldID.Require(Guid.Empty != fieldID, "fieldID");
return siteColumns.Contains(fieldID) ? siteColumns[fieldID] : null;
}
public SPFieldLookup CreateLookup(SPFieldCollection siteColumns, string fieldName, SPList lookupList, SPWeb web, bool required)
{
siteColumns.RequireNotNull("siteColumns");
fieldName.RequireNotNullOrEmpty("fieldName");
lookupList.RequireNotNull("lookupList");
string internalFieldName;
SPField looupField = TryGetField(siteColumns,fieldName);
if (null == looupField)
{
if (null != web)
{
internalFieldName = siteColumns.AddLookup(fieldName, lookupList.ID, web.ID, required);
}
else
{
internalFieldName = siteColumns.AddLookup(fieldName, lookupList.ID, required);
}
looupField = siteColumns.GetFieldByInternalName(internalFieldName);
}
return looupField as SPFieldLookup;
}
public static SPField TryGetField(SPFieldCollection siteColumns, string fieldName)
{
siteColumns.RequireNotNull("siteColumns");
fieldName.RequireNotNullOrEmpty("fieldName");
return siteColumns.ContainsField(fieldName) ? siteColumns.GetField(fieldName) : null;
}
