无法将值数组传递给对象数组

Question

I am trying to pass an array of values into an array of a table object so that I can write them to the database.

My database looks like this ->
tblCaseNotes
CaseNoteID | PersonId | etc, etc

tblCaseNotesContactType
rowguid | CaseNoteID | ContactTypeID

tblMaintItems
itemID | CategoryID

The itemID from the Maint table is what is being written to the tblCaseNotesContactType along with the current CaseNoteID. There can be multiple ContactTypes per CaseNote.

What I have so far is an array of the Values for the CheckListBox ContactType created in my btnNew_Click Event:

// Contact Type check list box
int cTypeCount = chkContactType.CheckedItems.Count;
int [] contactTypes = new int[cTypeCount];

// reusable generic counter for looping thru the check lists
int cMaintCounter = 0;

foreach (int checkedItem in chkContactType.CheckedIndices)
{
    contactTypes[cMaintCounter] = (int)chkContactType.GetItemValue(checkedItem);
    cMaintCounter++;
}
CurrentCaseNote.AddCNote(Program._CurrentPerson.PersonID, Convert.ToDecimal(tbxTimeSpentUnits.Text), chkIsCaseLog.Checked, Convert.ToDateTime(datContactDate.Text), memContactDetails.Text, contactTypes);

Which I then pass to my CurrentCaseNote object AddCNote method.

public static void AddCNote(int personID, decimal tsUnits, bool isCaseLog, DateTime cDate, string cDetails, int[] cTypes)
{
    var caseNoteToAdd = new tblCaseNote
                            {
                                CaseNoteID = Guid.NewGuid(),
                                PersonID = personID,
                                TimeSpentUnits =tsUnits,
                                IsCaseLog =isCaseLog,
                                ContactDate =cDate,
                                ContactDetails =cDetails,
                                InsertDate = DateTime.Now,
                                InsertUser = Environment.UserName
                            };

    tblCaseNotesContactType[] cTypeToAdd = new tblCaseNotesContactType[cTypes.Length];
    cTypeToAdd[0].CaseNoteID = caseNoteToAdd.CaseNoteID;
    cTypeToAdd[0].ContactTypeID =cTypes[0];
    cTypeToAdd[0].rowguid = Guid.NewGuid();

    CaseNoteDAL.addCNote(caseNoteToAdd,cTypeToAdd);

It is then passed to the DAL to be written to the local database:

public static void addCNote(tblCaseNote caseNote, tblCaseNotesContactType[] cType)
{
    foreach (var type in cType)
    {
        caseNote.tblCaseNotesContactTypes.Add(type);               
    }
    dcCaseNotes.tblCaseNotes.InsertOnSubmit(caseNote);

    //dcCaseNotes.tblCaseNotes.InsertOnSubmit(caseNoteToAdd);
    dcCaseNotes.SubmitChanges();
}

It is giving me a NUllReferenceException was unhandled error on this line --> cTypeToAdd[0].CaseNoteID = caseNoteToAdd.CaseNoteID;
Is it because I am only working with the [0]? I just did that to simplify my testing of this. When I step through the code my value array is correct and there is a Guid for caseNoteToAdd.CasNoteID

Can someone give me a few pointers on where I am going wrong here and what might be causing the error? As you can tell from my code I am new to this and I am learning on the fly.

Thanks,

~P

Answer 1

The problem is that you've created an array of reference types, but not populated it.

In other words, after this line:

tblCaseNotesContactType[] cTypeToAdd = new tblCaseNotesContactType[cTypes.Length];

you've got an array of null references - the value of each element is null.

You then need to write:

cTypeToAdd[0] = new tblCaseNotesContactType();

(or a similar statement) before you can start changing its properties.

An alternative would be to use an object initializer and do it in one statement (after creating the array):

cTypeToAdd[0] = new tblCaseNotesContactType
{
    CaseNoteID = caseNoteToAdd.CaseNoteID,
    ContactTypeID =cTypes[0],
    rowguid = Guid.NewGuid()
}: