C#, Generic, VS2008: Generic, class type, Byte Array

Sorry for deleting the previous thread by mistake, it was acceptable answer. I would like to thank for that.

I have other issue related to this

I have class which contains the byte array to store discrete hex data.....

#region//==================================================DataFrameGenericClass

public class DataFrameGenericClass

{

private UInt16 m_Page;

private Byte[] m_LIN_Array_Message1; // 7 byte Data + ID + CRC = 9 Byte Total

private Byte[] m_LIN_Array_Message2; // 7 byte Data + ID + CRC = 9 Byte Total

public DataFrameGenericClass(UInt16 Page)

{

this.m_Page = Page;

this.m_LIN_Array_Message1 = new Byte[9];

this.m_LIN_Array_Message2 = new Byte[9];

}

public UInt16 Page { get { return m_Page; } set { m_Page = value; } }

public Byte[] LIN_Array_Message1 { get { return m_LIN_Array_Message1; } set { m_LIN_Array_Message1 = value; } }

public Byte[] LIN_Array_Message2 { get { return m_LIN_Array_Message2; } set { m_LIN_Array_Message2 = value; } }

}

#endregion

I have Generic type with constraints

#region//==================================================DataFrameCollection

public class DataFrameCollection : IEnumerable where T : DataFrameGenericClass // "where T : Employee" Constraining type to Employee class only, (not to string or int).

{

List DataFrameList = new List();

public void Add(T element) // Add element at the bottom of the index (new data entry)

{

DataFrameList.Add(element);

}

public T Get(int index) // Get element at specfied index

{

return DataFrameList[index];

}

public void Update(int index, UInt16 Page) ///<<<<<< Previous C#Corner thread

{

T record = Get(index);

record.Page = Page;

}

public void Modify_LINArrayMessage1(int index, Byte[] message) // Modify element array at specfied index <<<<<< Previous C#Corner thread

{

T record = Get(index);

record.LIN_Array_Message1 = message;

//DataFrameList[index].LIN_Array_Message1 = message;

}

public void Modify_LINArrayMessage2(int index, Byte[] message) // Modify element at specfied index

{

DataFrameList[index].LIN_Array_Message2 = message;

}

public void Modify_Page(int index, UInt16 page16) // Modify element at specfied index

{

DataFrameList[index].Page = page16;

}

public void TraceDumpData(int index)

{

Trace.WriteLine("RawMessage:" + DataFrameList[index].RawMessage.ToString());

Trace.WriteLine("Page:"+DataFrameList[index].Page.ToString("X4"));

//### TODO Display LIN Array Message

}

//foreach support

IEnumerator IEnumerable.GetEnumerator()

{

return DataFrameList.GetEnumerator();

}

IEnumerator IEnumerable.GetEnumerator()

{

return DataFrameList.GetEnumerator();

}

#endregion

Then I have main code

DataFrameCollection DataFrameLIN = new DataFrameCollection();
.... I created the record

DataFrameLIN.Add(new DataFrameGenericClass(0));
DataFrameLIN.Add(new DataFrameGenericClass(1));
DataFrameLIN.Add(new DataFrameGenericClass(2));

.....

Byte[] LinAddress1 = new Byte[9];

Byte[] LinAddress2 = new Byte[9];

....

// Fill data with LinAddress1 and LinAddress2

LinAddress2[0] 0x01; LinAddress2[1] 0xFF; etc etc etc

I then update generic records, note that index = 0;

DataFrameLIN.Modify_LINArrayMessage1(0, LinAddress1);

DataFrameLIN.Modify_LINArrayMessage2(0, LinAddress2);

I then modify the LinAddress1 and 2

LinAddress2[0] 0x11; LinAddress2[1] 0x44; etc etc etc

I then update generic records, note that index = 1;

DataFrameLIN.Modify_LINArrayMessage1(1, LinAddress1);

DataFrameLIN.Modify_LINArrayMessage2(1, LinAddress2);

But during debug, I found that the array within index 0 has same value as index 1 array.

It seem it reference to LinAddress1 rather than value as this would explain same value. How to isolate reference between these two so it retains corrects value?

Thanks

PS:Again, very sorry for deleting the thread, it was a mistake as I click too quickly!

The problem here is that the records with indices 0 and 1 both have references to the same array objects. So when you change an element of the array in one record, it automatically changes the same element of the array in the other record.

To remedy this, you can either create new arrays each time you create new records or, if you want to base the contents of the new array on the old one, then you can use the Array.Clone() record.

To do the latter here, change the last few lines to:

// clone arrays

Byte[] LinAddress2_1 = (Byte[]) LinAddress2.Clone();

// I then modify the LinAddress1 and 2

LinAddress2_1[0] = 0x11;

LinAddress2_1[1] = 0x44; // etc etc etc

// add similar code to clone LinAddress1 to LinAddress1_1

// I then update generic records, note that index = 1

DataFrameLIN.Modify_LINArrayMessage1(1, LinAddress1_1);

DataFrameLIN.Modify_LINArrayMessage2(1, LinAddress2_1);

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
The problem here is that the records with indices 0 and 1 both have references to the same array objects. So when you change an element of the array in one record, it automatically changes the same element of the array in the other record.

To remedy this, you can either create new arrays each time you create new records or, if you want to base the contents of the new array on the old one, then you can use the Array.Clone() record.

To do the latter here, change the last few lines to:

// clone arrays

Byte[] LinAddress2_1 = (Byte[]) LinAddress2.Clone();

// I then modify the LinAddress1 and 2

LinAddress2_1[0] = 0x11;
LinAddress2_1[1] = 0x44; // etc etc etc

// add similar code to clone LinAddress1 to LinAddress1_1

// I then update generic records, note that index = 1

DataFrameLIN.Modify_LINArrayMessage1(1, LinAddress1_1);
DataFrameLIN.Modify_LINArrayMessage2(1, LinAddress2_1);