|
You can't do this. Object is the base class and Test the subclass. The Object type knows nothing about the Test type, so you can't create a new instance of Object and cast to Test.
Creating a new instance of Test and casting to Object is OK because Test derives from Object and therefore inherits its attributes and behaviour.
Paul Marfleet
"No, his mind is not for rent
To any God or government"
Tom Sawyer - Rush
|
|
|
|
|
Object obj = new Object();
Test test = new Test();
test = (Test)obj;
Now I have an InvalidCastException
System.InvalidCastException wurde nicht behandelt.
Message="Das Objekt des Typs System.Object kann nicht in Typ MyApplication.Test umgewandelt werden."
Source="MyApplication"
|
|
|
|
|
daniel99 wrote: Object obj = new Object();
Test test = new Test();
test = (Test)obj;
Now I have an InvalidCastException
How is this different to the code in your first post? It still won't work, for the reasons I outlined earlier.
I suggest you get a book on OOP and start reading.
Paul Marfleet
"No, his mind is not for rent
To any God or government"
Tom Sawyer - Rush
|
|
|
|
|
Hi
I have some question in c#
1. how can i pick some record in datagrid ?
2. how can i do that my program will open only one time ?
3. how can i send mail with Outlook in c# code ?
Thank's
|
|
|
|
|
I'll tackle part #3. Everything you want is in the System.Net.Mail namespace. Believe it or not, there's a web site dedicated to this namespace:
http://www.systemnetmail.com/[^]
|
|
|
|
|
thank's
i have more 2 question
1. how can i make XLS file to CSV in c# code ?
2. how can i zip and unzip files in c# code ?
|
|
|
|
|
Google SharpZipLib for information and code to use zip with c#.
My current favourite word is: PIE!
Good ol' pie, it's been a while.
|
|
|
|
|
how can i do that my program will open only one time ?
See this[^] article.
/ravi
|
|
|
|
|
Thank's alot
stil one question is unsolve
how can i pick some records in datagrid ?
|
|
|
|
|
E_Gold wrote: how can i pick some records in datagrid ?
To select a row, set its Selected property to true.
/ravi
|
|
|
|
|
hello
i need to use a binding navigator for a selection of a portion of a table in a dataset which i have created at runtime... and i have to code for binding navigator at runtime but don't know how it should be used.. .please provide help
haseeb
|
|
|
|
|
haseeb_saeed wrote: don't know how it should be used..
Be more specific. What is the trouble you are having?
"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus
|
|
|
|
|
Hi all ,
Using c# windows forms.
I have got 2 forms ; First is Main Form . Second is Report Form.
In my First Form , i have got a DataGridview Object.Im sorting selecting from db and send it to datagridview.It shows my Records. And a Button named "Report It.". Everything is OK.
In my second form , i have got a Crystral Report viewer obj.
Problem is ;
When i click "Report It" button thats in MY First Form.I want get the values from Datagridview obj. than send it to Crystal Report Obj thats in the MY Second Form and SHOW IT.!!!
its so simple isnt it ?
But i cant it. trying to do it from 2-3 weeks. 
|
|
|
|
|
tr_thorn wrote: its so simple isnt it ?
Yes, it is. Read the following article: http://www.codeproject.com/dotnet/passingvaluesbetweenforms.asp[^]
You should be able to pass the datagridview object using the methods the author talks about.
"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus
|
|
|
|
|
this isnt what i want  .. Iam a newbie programmer i want example please.
|
|
|
|
|
tr_thorn wrote: this isnt what i want
Then what is? The article shows how to pass values from one form to another. You can extend this by passing the whole object from one form to the next using the same principles that Colin talks about.
tr_thorn wrote: Iam a newbie programmer
I am not being harsh, but it sounds like you've bit off more than you can chew at this point.
You could always make the datagridview object be public and just grab it from the second form.
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
|
|
|
|
|
hi all,
im now doing the 'SearchEvent' using asp.net & C# on visualstudio2005,
where the user will search the event by selecting from the 3 dropdown boxes:
dropdownDay, dropdownMonth and dropdownYear.
It's suppose to query the 'start_date' from the ms access.
eg. 10-Mar-2004
im trying to write the query on it, but i kept getting the error when i run.
query:
string query = "SELECT code, description, start_date, start_time, venue FROM Event WHERE start_date = '" + dropdownDay.SelectedIndex.ToString() + " + ' - ' + " + dropdownMonth.SelectedIndex.ToString() + " + ' - ' + " + dropdownYear.SelectedIndex.ToString() + "' +";
Error message that appeared in visualstudio2005:
Syntax error (missing operator) in query expression 'start_date LIKE '%10 + ' - ' + 3 + ' - ' + 8%' +'.
i would appreciate some help on this line of code.
thanks! =D
|
|
|
|
|
your query is looking wrong
try this one
string query = "SELECT code, description, start_date, start_time, venue FROM Event WHERE start_date = '" + dropdownDay.SelectedIndex.ToString() + "' - '" + dropdownMonth.SelectedIndex.ToString() + "' - '" + dropdownYear.SelectedIndex.ToString() + "'";
Becoming Programmer...
|
|
|
|
|
thanks for the fast reply.
there isn't any error now, but i encounter some problems displaying my result in the gridview table.
when i run it, it doesn't displays any table/data at all, unlike my previous 'search by description' which is able to display out.
OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source =" + Server.MapPath("myFile..mdb") + ";");
conn.Open();
string query = "SELECT code, description, start_date, start_time, venue FROM Event WHERE start_date = '" + dropdownDay.SelectedIndex.ToString() + "' - '" + dropdownMonth.SelectedIndex.ToString() + "' - '" + dropdownYear.SelectedIndex.ToString() + "'";
OleDbDataAdapter comm = new OleDbDataAdapter(query, conn);
DataSet ds = new DataSet();
comm.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();
@__@ could you kindly guide me on this part?
thanks alot..
|
|
|
|
|
How can i read sqlconnection string from a text file.
|
|
|
|
|
tr_thorn wrote: How can i read sqlconnection string from a text file.
Why would you want to do that? You would typically store connection strings in the ConnectionStrings section of your app.config/web.config.
If you must read it from a text file, use the ReadAllText[^] method.
Paul Marfleet
"No, his mind is not for rent
To any God or government"
Tom Sawyer - Rush
|
|
|
|
|
use System.IO.File.ReadAllText or System.IO.File.ReadAllLines
hope it will help
Becoming Programmer...
|
|
|
|
|
can anyone gimme an example?
i m using windows forms c#.
|
|
|
|
|
SqlConnection dataConnection = new SqlConnection();
string connection = File.ReadAllText(filepath);
dataConnection.ConnectionString=connection;
hope it will help
Becoming Programmer...
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
