如何更新列表的项目值？

Question

i have a list. Where i put all my query output. Now do some processing using thread. so when work is completed then need to update the list item value. please see my code below:

publicly declared list:

public static List<string[]> OutboxList = new List<string[]>();

fetch the data from database and manipulate the list:

OutboxQueryCommand.CommandText = "SELECT top 5 id, status from TableA";      
SqlDataReader OutboxQueryReader = OutboxQueryCommand.ExecuteReader();

while (OutboxQueryReader.Read())
{
    string[] OutBoxFields = new string[7];
    OutBoxFields[0] = OutboxQueryReader["id"].ToString();
    OutBoxFields[1] = OutboxQueryReader["status"].ToString();
    OutboxList.Add(OutBoxFields);
}

foreach (string[] OutBoxFields in OutboxList)
{
    id = OutBoxFields[0];
    status = OutBoxFields[1];

    Thread OutboxThread = new Thread(() => OutboxThreadProcessor(id,status));
    OutboxThread.Start();
}

Call the method by thread:

 static void OutboxThreadProcessor(string id,string status)
   {
//predefine value of status is "QUE". Process some work here for that perticular item list.if data process success full then need to update 
// the status of the list item 

// need to update the perticular value of that list item here.
How i do it???????
//Say for Example 1-> Success
//            2-> Failed
//            3-> Success            
   }

Answer 1

You need to find an item in your list of arrays where item[0] is equal to id , and set the status into item[1] . You can do it with a loop, like this

foreach (string[] item in OutboxList) {
    if (item[0] == id) {
        item[1] = status;
        break;
    }
}

or with LINQ, like this:

var item = OutboxList.FirstOrDefault(a => a[0] == id);
if (item != null) {
    item[1] = status;
}

Note that your data structures are not particularly object-oriented. Your program would be more readable if you replaced an array of seven string items with a class that has seven string fields, like this:

class OutBoxFields {
    public string Id {get;set;}
    public string Status {get;set;}
    ... // and so on
}

Answer 2

Pass the array directly to Thread so that you can update the array once you're done.

static void OutboxThreadProcessor(string[] OutBoxFields)
{
    string id = OutBoxFields[0];
    string status = OutBoxFields[1];

    //Do work

    OutBoxFields[0] = "2";//update the array
    OutBoxFields[1] = "something";
}

Call it like this

Thread OutboxThread = new Thread(() => OutboxThreadProcessor(OutBoxFields));
OutboxThread.Start();

Also note that you're closing over the loop in this scenario, this is fine if you're building in c#5.0 compiler this is fine, else you need to use a local variable inside the loop.