Entities in 'eDocEntities.Document' participate in the 'FDocumentDocumentTypeId' relationship. 0 related 'DocumentType' were found. 1 'DocumentType' is expected.

		private void DeleteEDocument() {
			string fileName = this.grdData.CurrentRow.Cells["FileName"].Value.ToString();
			if (MessageBox.Show(string .Format("Delete \"{0}\"?", fileName), "eDoc",
				MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes) {
				object documentIdValue = this.grdData.CurrentRow.Cells["DocumentId"].Value;
				Guid documentId = new Guid(documentIdValue.ToString());
				Document documentToDelete = new Document();
				documentToDelete.Id = documentId;
				documentToDelete.EntityKey = new EntityKey("eDocEntities.Document", "Id", documentId);
				context.Attach(documentToDelete);
				context.DeleteObject(documentToDelete);
				context.SaveChanges();
			}
		}