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I have something like this:
string a=string.Empty;
if(b!=a){}
from this i can check if b is a empty variable for the condition of the if loop.
there isn't any int.Empty, how can i do the same if i want to compare if a int variable in empty for a if loop?
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An int when declared is initialised to 0 if i am not wrong, or just rubbish value. Either way, they can't be "empty".
<font=arial>Weiye Chen
Life is hard, yet we are made of flesh...
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Vikram A Punathambekar wrote:
Not rubbish, only 0s in C#
Yeah, thanks for confirming that. 
<font=arial>Weiye Chen
Life is hard, yet we are made of flesh...
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The property string.Empty is just a static string with the value "".
string a = string.Empty;
has the same effect as:
string a = "";
The only difference is that the second one creates a new string object, while the first one uses the empty string that already exists.
As there is no gain in having static instances of value types, there isn't any static zero constant. Just use the value zero:
int a = 0;
---
b { font-weight: normal; }
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hi
i have some experience in c++ and vc++
i want to migrate to .net
would u tell me which language should i learn first for .net??
ive heard that c# is the mother of .Net .so i should learn c# first or go directly to visual c++.net??
and also i awnt to learn asp.net what should i do?
thx
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The is no difinitive answer to that question.
I work with c# because my background experience is in Java, and the similarities made it easy to migrate from Java to c#. Also most of the readily available books on writing Windows apps. and asp.net web form's are orientated around c# and VB, although i'm sure it is easy to get hold of books orientated around c++.
The beauty of Visual Studio.net is that all the language's have more or less the same level of functionality.
Check out http://msdn.microsoft.com/vstudio/productinfo/topten/upgrade.aspx
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t-seanm wrote:
I work with c# because my background experience is in Java,
Out of curiosity, what reasons did you have for trying .NET? Does .NET provide anything significant over what the Java frameworks do?
Kevin
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Well to tell u the truth the only reason I took up .Net is I am currently an intern in Microsoft Ireland. But there are so many advantages...
The excellent help section that comes with Visual Studio and online, not to mention the code samples.
The Microsoft press release contains tonnes of book for helping developers do just about anything.
You have to pop-up menus that appear each time you use dot notation, telling you what methods are available to you.
I always wanted to learn to use ASP.NET and with talking to people here at MS Ireland, c# or VB are the languages of choice for ASP.NET applications. Since c# is similar to Java, I chose it over the other languages. I picked it up quite easily, and i've never been a fan of VB, the syntax annoys me for some reason.
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Don't you get similar help and samples with Java?
Kevin
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Hello
It all depends upon the kind of Background u come from, by that i mean which language you are well versed with. Since you have been using C++ and vc++ earlier it would make things easier for you if u go for VC++.net.
As for C# it's Language worth learning and easy to pick up too.
best of luck!!!
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I have a class to which I can pass any SQL query and it can return “DataReader” object or “DataSet” etc. To achieve this I have different methods in that class.
What is the best way to use database connection in ASP.NET application? I would like to use connection pooling too. Database is SQL Server 2000. Should we use singleton class in this, if yes, how can we use?
I appreciate your help.
![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
- ashish
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Connection pooling in ASP.NET happens all by itself, you can just create connections as you need them, I believe.
Christian Graus - Microsoft MVP - C++
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Yes, while using SqlClient and in connection string saying "connection pooling=true" automatically create connection pool for the same connection string.
What if there are multiple threads needs connection at same time? The error I get is, all the connection in connection pool are in use, and connection timed out. So I thought that this should not be the best way to use ADO.NET in ASP.NET
- ashish
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You can change how many connections are in the pool, I believe. Other than that, I'm not sure. We just create connections as we need them and don't have any troubles.
Christian Graus - Microsoft MVP - C++
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You can also specify "Max Pool Size" and "Min Pool Size" to adjust your pool. But I think this is specific to SQL Server only.
Thanks.
modified 17-Jul-19 21:02pm.
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Here's my code:
public void dgTickets_Update(Object sender, DataGridCommandEventArgs e){<br />
string tdate, tnum, tcID, tter, tsc, tcu, tloc, tinfo, tid;<br />
<br />
tdate=((TextBox)e.Item.Cells[1].Controls[0]).Text;<br />
tnum=((TextBox)e.Item.Cells[2].Controls[0]).Text;<br />
tcID=((TextBox)e.Item.Cells[3].Controls[0]).Text;<br />
tter=((TextBox)e.Item.Cells[4].Controls[0]).Text;<br />
tsc=((TextBox)e.Item.Cells[5].Controls[0]).Text;<br />
tcu=((TextBox)e.Item.Cells[6].Controls[0]).Text;<br />
tloc=((TextBox)e.Item.Cells[7].Controls[0]).Text;<br />
tinfo=((TextBox)e.Item.Cells[8].Controls[0]).Text;<br />
tid=((TextBox)e.Item.Cells[9].Controls[0]).Text;<br />
<br />
string sSqlCmd = "UPDATE MCI_Tickets SET t_date = ?, t_num = ?, t_circuitID = ?, t_ter = ?, t_sc = ?, t_cu = ?, t_loc = ?, t_info = ? WHERE t_id = ?";<br />
SqlConnection updCon = new SqlConnection(Conn);<br />
SqlCommand updCmd = new SqlCommand(sSqlCmd, updCon);<br />
<br />
updCmd.Parameters.Add(new SqlParameter("@t_date", SqlDbType.Char, 10));<br />
updCmd.Parameters["@t_date"].Value = tdate;<br />
updCmd.Parameters.Add(new SqlParameter("@t_num", SqlDbType.Char, 5));<br />
updCmd.Parameters["@t_num"].Value = tnum;<br />
updCmd.Parameters.Add(new SqlParameter("@t_circuitID", SqlDbType.Char, 15));<br />
updCmd.Parameters["@t_circuitID"].Value = tcID;<br />
updCmd.Parameters.Add(new SqlParameter("@t_ter", SqlDbType.Char, 5));<br />
updCmd.Parameters["@t_ter"].Value = tter;<br />
updCmd.Parameters.Add(new SqlParameter("@t_sc", SqlDbType.Char, 6));<br />
updCmd.Parameters["@t_sc"].Value = tsc;<br />
updCmd.Parameters.Add(new SqlParameter("@t_cu", SqlDbType.Char, 6));<br />
updCmd.Parameters["@t_cu"].Value = tcu;<br />
updCmd.Parameters.Add(new SqlParameter("@t_loc", SqlDbType.NVarChar, 50));<br />
updCmd.Parameters["@t_loc"].Value = tloc;<br />
updCmd.Parameters.Add(new SqlParameter("@t_info", SqlDbType.NVarChar, 50));<br />
updCmd.Parameters["@t_info"].Value = tinfo;<br />
updCmd.Parameters.Add(new SqlParameter("@t_id", SqlDbType.Int, 4));<br />
updCmd.Parameters["@t_id"].Value = tid;<br />
<br />
updCon.Open();<br />
updCmd.ExecuteNonQuery();<br />
updCon.Close();
I keep getting the error:
Incorrect syntax near '?'
all the values show correct when i run through the Locals in the debugger. Would it be a problem with the database?
TIA,
Scott
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sonicsqwirl wrote:
string sSqlCmd = "UPDATE MCI_Tickets SET t_date = ?, t_num = ?, t_circuitID = ?, t_ter = ?, t_sc = ?, t_cu = ?, t_loc = ?, t_info = ? WHERE t_id = ?";
sonicsqwirl wrote:
Incorrect syntax near '?'
Obviously, the ? are still in the code. I've never seen this syntax anywhere, do you have a reference to indicate that it should work ?
Christian Graus - Microsoft MVP - C++
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yes we used it in school on an application that updates an Access database ex. Code:
string sSqlCmd = "UPDATE Parts SET Name = ?, Description = ?, Price = ? WHERE PartID = ?";<br />
<br />
updCmd.Parameters.Add(new OleDbParameter("@PartDescription", OleDbType.VarWChar, 100));<br />
updCmd.Parameters["@PartDescription"].Value = sPartDescription;<br />
updCmd.Parameters.Add(new OleDbParameter("@PartPrice", OleDbType.Currency));<br />
updCmd.Parameters["@PartPrice"].Value = sPrice;<br />
updCmd.Parameters.Add(new OleDbParameter("@PartID", OleDbType.Integer));<br />
updCmd.Parameters["@PartID"].Value = sPartID;<br />
<br />
updCon.Open();<br />
updCmd.ExecuteNonQuery();<br />
updCon.Close();
any ideas on how i can do this differently?
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Well, the most obvious way would be to use a stringbuilder to build the SQL, or even the string.Format method. I would have expected to only add parameters when calling a stored procedure. If a stored proc is an option here, I'd go with that instead.
I've just checked, and MSDN says this:
The .NET Framework Data Provider for SQL Server does not support the question mark (?) placeholder for passing parameters to a Transact-SQL statement or a stored procedure called by a command of CommandType.Text. In this case, named parameters must be used. For example:
SELECT * FROM Customers WHERE CustomerID = @CustomerID
In other words, if you change the ? to the same paramater names as the names you're using to add paramaters, then this approach will work, and is probably the best way to go outside of using a stored procedure. The main problem with this approach is that it opens you to SQL Injection attacks.
Christian Graus - Microsoft MVP - C++
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Isn't that the syntax for using the ODBC adapter with named paramters?
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Yes, so I learned. I've never used the ODBC adapter before. Beats me why it differs.
Christian Graus - Microsoft MVP - C++
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After installing the Oracle ODT I find that now I can access all my Oracle 10 databases perfectly, but the older Oracle 8i systems are no longer available.
I understand this is a known problem, has anyone else encountered this and knows of a work around ?
Thanks
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One thing to look at is the tnsnames.ora files. The ODT stuff creates a new set for 10g (separate from the ones for 9i etc.), and they may be different but the 10g version is sometimes the only one used after it is created. If the name resolutions of all your databases are not in the 10g version of tnsnames.ora, then you might consider merging the tnsnames.ora files.
Another potential problem is that ODT also creates a sqlnet.ora file that works sort of like your hosts file (helps resolve server names). In my case, the sqlnet.ora file had incorrect domain information that was overriding what was in my tnsnames.ora file and causing server names not to resolve. After some fiddling with the file, I finally just deleted it, reasoning that it had not been there prior to ODT, and everything had worked fine anyway. Everything worked after that.
Hope this helps.
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’
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hi guys,
i have been playing with the DSOFile component from MS. One of the things I realised it couldnt do was to read properties of PDF documents. So I have managed to rectify this by simply using the shell32.dll and using the GetFileInfo method from that dll.
However, my problem is that how do i save the summary file properties of a PDF document if I am using shell32.dll ??
I have tried looking through MSDN but couldnt find anything. Any suggestions will be appreciated.
Thanks
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