how to make a void returning a datatable?

Question

I want to use multithreading for the first time as I understood, there is 2 laws to respect: -Threads can be used only with void's -One cannot use Threads to change something in a windows form(unless you use delegates).

So I code my macro by respect to this rule, here is my code :

public void exec_RT(string tickername, bool isSubIndex)
{
    DataTable RT_dt = Price_dt(tickrname, isSubIndex);
    Infragistics.Win.UltraWinChart.UltraChart toplot = new Infragistics.Win.UltraWinChart.UltraChart();
    toplot = forms.Real_timeAlpha;
    configgraph(RT_dt, toplot);
}

My problem is that the function Price_dt return a datatable :

public DataTable Price_dt(string tickername, bool isSubIndex)
{
    DoMyThing();
    return real_time;
}

So my question is how can I make a void return a datatable ?

Thanks

I don't know much about multi threading but you can achieve this by using out parameter. — PM., Aug 23 '13 at 14:14
`Threads can be used only with void's` - Not true. Take a look at the TPL for this. — Federico Berasategui, Aug 23 '13 at 14:16
Have you tried using callbacks? Check this article for inspiration http://blog.bitlinkit.com/asynchronous-callback-threading-in-c/ — Gonzix, Aug 23 '13 at 14:46

score 0 · Answer 1 · answered Aug 23 '13 at 14:18

you can use class members for storing the datatable.

public DataTable Price_dt(string tickername, bool isSubIndex)
{
    DoMyThing();
    this.setDT(real_time);
}

i'm pretty sure you have to (/should) use an invoke for setting the table (therefore the function).

you can reffer the "stored" table in every other part of your class.

hope this helps

Rémi · Answer 2 · 2015-02-04T16:10:03.120

0

You could just pass the DataTable to your method and work in that table. Since DataTable is a reference type all your modification are on the original object to witch both variables reference (your original variable and the one from inside Price_dt).

Your method would go from this

public DataTable Price_dt(string tickername, bool isSubIndex)
{
    DoMyThing();
    return real_time;
}

to this

public void Price_dt(DataTable yourDataTable, string tickername, bool isSubIndex)
{
    //modify yourDataTable here
    DoMyThing();
}

edited Feb 04 '15 at 16:10

answered Aug 23 '13 at 14:22

Rémi

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you still can't return `real_time` you have to `yourDataTable = real_time` (i hope that `real_time` is the table ... it's not clear (for me) – Alex Aug 23 '13 at 14:38
@Alex of course I simply add forgot to remove the `return` statement. the datatable will be modified outside of the method without having to return it. – Rémi Aug 23 '13 at 14:41
I just tried it the idea is nice but it does not work , the Datatable yourDataTable come back empty in exec_RT – francops henri Aug 23 '13 at 15:04
@francopshenri how have you tryed? I use this kind of behavior at several place in my code and it work properly – Rémi Aug 23 '13 at 15:28

score 0 · Answer 3 · answered Aug 23 '13 at 14:24

You could try to use a global variable to store your DataTable in

public void exec_RT(string tickername, bool isSubIndex)
    {
        DataTable RT_dt = Price_dt(tickrname, isSubIndex);
        Infragistics.Win.UltraWinChart.UltraChart toplot = new Infragistics.Win.UltraWinChart.UltraChart();
        toplot = forms.Real_timeAlpha;
        //global variable of the type DataTable
        globalTable = RT_dt;
        configgraph(RT_dt, toplot);
    }

And use globalTable for whatever you may need later on.

how to make a void returning a datatable?

3 Answers3