c# - making a .NET TextBox work FIFO style -

-

i have win gui application written in c#, in have textbox component write log to. @ point gets loaded , entire app starting falter. i'd make efficient mechanism make fifo, meaning - make fixed size , deleting oldest content automatically.

is there .net/c# feature doing that? otherwise, right way this?

update: have issue other sort of textual data, , not logs. therefor, listbox not proper solution me.

to create circular buffer text, i'd use stringbuilder, capacity set twice amount of data want display.

const int displaysize = 10000; stringbuilder fifo = new stringbuilder(2 * displaysize);  string appendtofifo( string s ) {     if (s.length >= displaysize) {         // fact: display include data s         // therefore, toss entire buffer, , keep tail of s         fifo.clear();         fifo.append(s, s.length - displaysize, displaysize);         return fifo.tostring();     }     if (fifo.length + s.length > fifo.capacity) {         // fact: overflow fifo         // therefore, keep data in fifo remains on display         fifo.remove(0, fifo.length + s.length - displaysize);     }     fifo.append(s);     if (fifo.length <= displaysize) {         // fact: entire fifo content fits on display         // therefore, send         return fifo.tostring();     }     // fact: fifo content exceed display size     // therefore, extract tail     return fifo.tostring(fifo.length - displaysize, displaysize); }

the fast path, when none of if conditions true, avoids unnecessary copies (in .net world strings immutable, final copy create output string cannot avoided). , in other cases needed characters copied. increasing capacity of buffer improve utilization fraction of fast path. i've been careful avoid doing creating string object old content remains on display, has no purpose except concatenate new content, , becomes garbage.

obviously, if use p/invoke pass pointer stringbuffer's content instead of copying out substring, more efficient.


Comments

Post a Comment

Popular posts from this blog

c# - How Configure Devart dotConnect for SQLite Code First? -

-
can configure following sample code ? when run following code, error : no entity framework provider found ado.net provider invariant name 'devart.data.sqlite' setting in machine.config <system.data> <dbproviderfactories> <add name="dotconnect sqlite" invariant="devart.data.sqlite" description="devart dotconnect sqlite" type="devart.data.sqlite.sqliteproviderfactory, devart.data.sqlite, version=4.6.287.0, culture=neutral, publickeytoken=09af7300eec23701" /> </dbproviderfactories> </system.data> after add below block code in app.config <?xml version="1.0"?> <configuration>   <configsections> <!-- more information on entity framework configuration, visit http://go.microsoft.com/fwlink/?linkid=237468 --> <section name="entityframework" type="system.data.entity.internal.configfile.entityframeworksection, entit...
Read more

c++ - Clear the memory after returning a vector in a function -

-
i have function processes , stores lot of data in , returns results vector of class. amount of data stored in function tremendous , want clear storage memory of function after finished job. necessary (does function automatically clear memory) or should clear memory function? update: vector<customers> process(char* const *filename, vector<int> id) { vector<customers> list_of_customers; (perform actions) return list_of_customers; } variables defined locally within function automatically released @ end of function scope. destructors objects called, should free memory allocated objects (if objects coded correctly). example of such object std::vector . anything you've allocated new must have corresponding delete release storage. try avoid doing own allocation , use raii instead, i.e. containers or smart pointers.
Read more

erlang - Saving a digraph to mnesia is hindered because of its side-effects -

-
updated the digraph library in erlang implements data type side-effectful. each operation on data type saves new state in ets table -- instead of returning altered version of itself, more common in functional languages. the problem usage perspective, impedes effort store or pass around state in convenient way requiring me first "collect" state before can start juggle around. the closest solution have seen far serializer/deserializer , these have drawback tied current structure of digraphs instead of operating on abstract type -- prevents future proof solution. update pascal pointed out serializer utilizes interface of digraph, , hence eliminates drawback mentioned above. better, albeit still inconvenient, see no better alternative. what recommendation on how store digraphs? should go different data type altogether? thanks. i not sure understand concern. fact digraph stored in ets transparent in user interface, might want chnge either exchange digr...
Read more