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Hello Guys,
I am Developing an Application in Visual Studio 2012 to get some heat transfer parameters as output with some temperature/area inputs. The equations that I want to code in for getting a "heat Transfer Coefficient" are non-linear in nature with cube roots and fourth roots. Such equations can be solved in a single line of code in Mathematica or Matlab but Visual Studio I dont know how can I solve them and return the value. Any help will be appreciated. A sample of such equations in one variable is listed below:
[2*[T+298]^3 + 1.2 * (T-298)^1/3]* [T-298]= [338-T]/0.2
I have to solve for T.
Thank you in Advance.
Nadish
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I'd try an interative approximation: start with some value for T, calculate the formula, change T a little, calculate again, compare the results, and decide for another approximation of T, till you think your result is sufficiently "exact".
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Is it the Fully Qualified Type Name?
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I think the basic idea for the syntax of a "generic" parameter in .NET is that it can be any group-of-glyphs (set of characters) that meaningfully serve as a "place-holder" that will hold, at run-time, any valid .NET Type.
A convention that has developed, and which is used in many books about C# .NET ... though I am not sure it has ever been formalized in the C# language specification ... is to use single characters like "T," and "U," etc., for generic parameter names.
In terms of the syntax of the .NET Types you pass to some Method that receives generic parameters, I think whether or not you must use a fully qualified Type Name depends on the name-scope context in effect at the moment you wish to pass the Type.
So, if you have valid "using" statements in effect, then you can just pass the current valid variable name by itself; if the context does not already provide the ability to use the current name alone, then you must use the fully qualified Type name. Hopefully, you would get a compile-time error if you did not include all the required access syntax for any variable.
Am I understanding what you are asking here correctly ?
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
modified 17-Mar-14 2:13am.
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BillWoodruff wrote: Am I understanding what you are asking here correctly ?
Nope, but that's because I didn't explain to well.
Let me elaborate.
If I have a Generic class Generic<T> and two normal classes ClassA and ClassB that can be used as Generic<ClassA> and Generic<ClassB> .
How does the Generic<T> class (or actually the compiler) tell the two classes apart? What does the compiler use to identify a class?
The reason that I was asking is that I was trying to use generics with dynamically created classes.
Which of course doesn't work, because the compiler doesn't know about those classes at compile time.
So today the question is merely of academic value to me. But atleast I've learned how to create a class at runtime.
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The clue is in the IL. Consider this assembly:
namespace JorgenQuestion
{
class Program
{
static void Main(string[] args)
{
Chooser<ClassA> chooser = new Chooser<ClassA>();
Chooser<ClassB> chooser2 = new Chooser<ClassB>();
}
}
public class ClassA
{
}
public class ClassB
{
}
public class Chooser<T>
{
}
} Now, the IL that's produced out for the Program class is this:
.class private auto ansi beforefieldinit JorgenQuestion.Program
extends [mscorlib]System.Object
{
.method public hidebysig specialname rtspecialname instance void .ctor () cil managed
{
IL_0000: ldarg.0
IL_0001: call instance void [mscorlib]System.Object::.ctor()
IL_0006: ret
}
.method private hidebysig static void Main (
string[] args
) cil managed
{
.entrypoint
.locals init (
[0] class JorgenQuestion.Chooser`1<class JorgenQuestion.ClassA> chooser,
[1] class JorgenQuestion.Chooser`1<class JorgenQuestion.ClassB> chooser2
)
IL_0000: nop
IL_0001: newobj instance void class JorgenQuestion.Chooser`1<class JorgenQuestion.ClassA>::.ctor()
IL_0006: stloc.0
IL_0007: newobj instance void class JorgenQuestion.Chooser`1<class JorgenQuestion.ClassB>::.ctor()
IL_000c: stloc.1
IL_000d: ret
}
} As you can see, the newobj statements are instantiating the correct classes.
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That's fascinating, Pete: thanks !
I am trying to imagine a real-world scenario in which using the type of generic Classes in this example would be useful, but drawing a blank. Any ideas ?
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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I can't come up with anything either.
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Thanks for confirming.
I wish I could give you an extra upvote for doing it by example.
My knowledge map sadly says "Here be monsters" where it should say IL.
So that's added on my todo list.
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You're welcome. I do find that dropping down to the IL can be a real eye opener at times.
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Do you have any reading to recommend, or should I just get my hands dirty?
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Just get your hands dirty. I learned IL by writing simple, predictable console applications that exercised different parts of the language and then I looked to see what was produced. Of course, I was lucky enough to be forced down this route because I wrote a code generator back in about 2004 and I had to really get my head around the way IL worked to fully understand what I was producing.
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I have the following objects:
public class Parent
{
public BaseChild Child {get;set;}
}
public class BaseChild
{
}
public class ChildOne : BaseChild
{
public string Member {get;set;}
}
"Parent" is mapped to a "Parent2" type from a different module (which has the same member BaseChild).
Mapper.CreateMap(typeof(Parent), typeof(Module2::Parent2));
Mapper.CreateMap(typeof(BaseChild), typeof(Module2::BaseChild));
Mapper.CreateMap(typeof(ChildOne ), typeof(Module2::ChildOne ));
I'm creating a Parent object:
Parent parent = new Parent
{
Child = new ChildOne { Member = "Test" }
}
And try to convert:
object parent2 = Mapper.Map(parent, parent.GetType(), typeof(Module2::Parent2));
I get the following exception from auto mapper:
----------
{AutoMapper.AutoMapperMappingException: Missing type map configuration or unsupported mapping.
Mapping types:
ChildOne -> BaseChild
Test.ChildOne -> Test.BaseChild
----------
I need this mapping to work in order to be able to convert objects from a new "Parent2" type (in the 2nd module) to an old one.
How do I make it support inherited types of members in a converted class?
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Hi,
I am able to use API DllImport("user32.dll") for FindWindow, GetCursorPosition then use sendkys to enter some number\text into an other GUI application ... through its Title & Class (ie: Windows Calculator!
However if I don't use API Mouse to move in other sections ... I can't not go directly them (with Autoit I can use with Title & Advanced Class = Advanced (Class): [CLASS:Button; INSTANCE:72] )
My question is there any way I can do that with Vsual C# and How?
Thanks to any help
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Well, it AutoIt, there is code behind the scenes that is parsing and interpreting that "Advanced (Class): [CLASS:Button, INSTANCE:72])" stuff. There is NOTHING in the Windows API that has any idea what that string means or what to do with it.
You're asking about how to write the code that AutoIt has inside that does just that. For that, you would have to ask the people who wrote AutoIt. Good luck with that!
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Might be the way I asking wasn't right, I do work well with Autoit ... but I have to work with Visual C# now! I am not expert in Visual C#, that was why I would like to know there is a similiar way to access direct an instance of a GUI or not? I thought Visual C# a well-known SW should have a better way than a free Autoit (it can't even build a DLL or a distribution application)
If there isn't a way, then I will have to use mouse method to move to the area I want to access ... but this ia the bad way, because if the people move the GUI to other position or change the screen resolution ... the mouse will move to wrong location
I hope that you aren't upset because of a people who just wants to know there is any thing available
modified 16-Mar-14 16:08pm.
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Member 10636998 wrote: I would like to know there is a similiar way to access direct an instance of a GUI or not
No, there isn't. The only way you've got is the one you're already using, FindWindow, ...
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Hi Dave,
In this case I don't have to search for it any more!
Thanks for the confirmation.
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I want to create an application where I can load the excel file or the set the path in the code(hard coded) and the program will create the table in SQL Server. The data in the top column will be the name of the fields.
Assuming that Database is already created and the name of excel file will be the name for the table.
So I want to know how to approach this task and what things I need to consider.
Thanks
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It's not something I've done, but...
Loading Excel data to a DataTable is pretty easy:
public static System.Data.DataTable LoadExcel(string path, string columns = "*", string sheet = "Sheet1$", bool verify = true)
{
if (verify)
{
if (!File.Exists(path)) throw new IOException("The input file does not exist: " + path);
if (!GetExcelSheetNames(path).Contains(sheet)) throw new ArgumentException("The requested sheet does not exist: " + sheet);
}
if (string.IsNullOrWhiteSpace(columns)) columns = "*";
System.Data.DataTable dt = new System.Data.DataTable();
using (OleDbConnection con = new OleDbConnection(GetExcelConnectionString(path)))
{
con.Open();
string cmdStr = string.Format("SELECT {0} FROM [{1}]", columns, sheet);
using (OleDbCommand cmd = new OleDbCommand(cmdStr, con))
{
using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
{
da.Fill(dt);
}
}
}
return dt;
}
public static List<string> GetExcelSheetNames(string path)
{
List<string> sheetNames = new List<string>();
using (OleDbConnection con = new OleDbConnection(GetExcelConnectionString(path)))
{
con.Open();
using (DataTable sheets = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null))
{
foreach (DataRow sheet in sheets.Rows)
{
if (sheet["TABLE_NAME"].ToString().Contains("$"))
{
sheetNames.Add(sheet["TABLE_NAME"].ToString());
}
}
}
}
return sheetNames;
}
private static string GetExcelConnectionString(string path)
{
return string.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0}; Extended Properties=Excel 12.0", path);
}
And then you need to do is create the DB table from the DataTable. And that is already done as well...if not by me: http://darrylagostinelli.com/2011/06/27/create-a-sql-table-from-a-datatable-in-c-net/[^]
Finally, bulk copy the data over:
public static void LoadSql(string strConnect, string tableName, DataTable table)
{
using (SqlConnection con = new SqlConnection(strConnect))
{
try
{
con.Open();
using (SqlBulkCopy bulk = new SqlBulkCopy(con))
{
bulk.DestinationTableName = tableName;
bulk.WriteToServer(table);
}
}
finally
{
con.Close();
}
}
}
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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It's bad practice! It could cause several problems, like: unable to add table with the name of existing one, unable to manage the tons of tables, etc.
Please, refer this: Maximum Capacity Specifications for SQL Server[^]
Tables per database are limited by the number of objects in a database. Database objects include objects such as tables, views, stored procedures, user-defined functions, triggers, rules, defaults, and constraints. The sum of the number of all objects in a database cannot exceed 2,147,483,647 (MS SQL Server 2012).
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It may not be perfect practice, but it's something quite useful - I keep several "odds and ends" in Excel format that should really be in SQL, and being able to transfer the data from the one to the other makes life a lot easier (I'm tidying up the code in my link at the moment, because it's pretty poorly written). Once I'm finished, I'll transfer half a dozen of my Excel sheets to SQL and convert the spreadsheets to C# forms instead.
I suspect it's not something he wants to do every day, but he wants to avoid the potential errors involved in a manual transfer. Thinking about it, I may knock up a utility to do it as well - prototyping the DB is a lot easier in Excel than in SSMS where you have to keep switching about to / from design mode.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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Ok, i can agree with it only in case when it happens once on a long time.
BTW: Both your answers have been upvoted!
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OriginalGriff wrote: and being able to transfer the data from the one to the other makes life a lot easier
Just to clarify... The OP was asking about creating a table not loading data.
So are you referring to creating tables or loading data?
And if you are creating tables are you referring to a standard business table or just something like an enumeration table?
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