Solved

The Using statement in C#

Posted on 2016-10-24
5
50 Views
Last Modified: 2016-10-24
To date, I've been creating a public static class for connecting to host databases, and passing back a connection object. That entails closing the connection and disposing of all the associated objects.
I recently saw code that showed a using statement; I've really only used "using" declarations at the beginning of my code.
I see all of the examples online but none show the entire code for the class. Is there someone out there who'd like to share?
If you have any tips on implementing, I'm all ears!
0
Comment
Question by:Euless_Tech
5 Comments
 
LVL 21

Assisted Solution

by:Tapan Pattanaik
Tapan Pattanaik earned 125 total points
ID: 41857643
Hi Euless,

This is the sample example.

-----------------------------------------////////////////Step 1////////////////----------------------------------------
<configuration>
  <connectionStrings>
    <add name="CharityManagement" 
    connectionString="Data Source=.;Initial Catalog=CharityManagement;Integrated Security=True"/>
  </connectionStrings>
</configuration> 

---------------------------------///////////////////Step 2/////////////////////-----------------------------------------------------

var connectionString=ConfigurationManager.ConnectionStrings["CharityManagement"].ConnectionString;

---------------------------------//////////////////Step 3////////////////--------------------------------------------
using (SqlConnection connection = new SqlConnection(connectionString)) 
{    
  int employeeID = findEmployeeID();    
  try    
  {

            connection.Open();
            SqlCommand command = new SqlCommand("UpdateEmployeeTable", connection);
            command.CommandType = CommandType.StoredProcedure;
            command.Parameters.Add(new SqlParameter("@EmployeeID", employeeID));
            command.CommandTimeout = 5;

            command.ExecuteNonQuery();    
   } 
   catch (Exception) 
   { 
      /*Handle error*/ 
   }

}

Open in new window

0
 
LVL 12

Accepted Solution

by:
Dustin Saunders earned 250 total points
ID: 41857649
I always use using for my SQL connections (so much less to clean up).  Here is an example of my function I use to execute inserts/updates:

        public static void WriteSQL(string sqlQuery, DataTable parameters = null)
        {
            string cs = GetConnectionString();
            using (SqlConnection _cs = new SqlConnection(cs))
            {
                SqlCommand cmd = new SqlCommand(sqlQuery);

                PutParameters(cmd, parameters);

                cmd.CommandType = System.Data.CommandType.Text;
                cmd.Connection = _cs;
                _cs.Open();
                cmd.ExecuteNonQuery();
            }
        }

Open in new window


(for reference, here is PutParameters)
        public static void PutParameters(SqlCommand cmd, DataTable parameters)
        {
            if (parameters != null)
            {
                foreach (DataRow row in parameters.Rows)
                {
                    if (row[2].ToString() == "int")
                    {
                        cmd.Parameters.Add(row[0].ToString(), SqlDbType.Int).Value = Convert.ToInt32(row[1]);
                    }
                    else if (row[2].ToString() == "varchar")
                    {
                        cmd.Parameters.Add(row[0].ToString(), SqlDbType.VarChar).Value = row[1].ToString();
                    }
                }
            }
        }

Open in new window

0
 

Author Comment

by:Euless_Tech
ID: 41857674
Either one of you that responded ever nest the using statements?
0
 
LVL 20

Assisted Solution

by:Daniel Van Der Werken
Daniel Van Der Werken earned 125 total points
ID: 41857687
The key factor for the Using statement is that the class  you're coding to implements IDisposable.

While I use this a lot, there are some cases where you wouldn't want to. For example, you might need a "handle" to the object outside of the open/close operations.

Most of the time though, you want to wrap everything you can in a using statement. Here's my example with iTextSharp. Note I've wrapped all the usings and this gives me a clean process.

                    using (Document iTextDocument = new Document(PageSize.A4, 0, 0, 0, 0))
                    {
                        using (FileStream sw = new FileStream(outputPDF, FileMode.Create))
                        {
                            using (PdfWriter pdfWriter = PdfWriter.GetInstance(iTextDocument, sw))
                            {
                                using (Bitmap bitmap = new Bitmap(inputTIFF))
                                {
                                    int pageCount = bitmap.GetFrameCount(FrameDimension.Page);
                                    iTextDocument.Open();
                                    PdfContentByte contentByte = pdfWriter.DirectContent;
                                    for (int i = 0; i < pageCount; i++)
                                    {
                                        bitmap.SelectActiveFrame(FrameDimension.Page, i);
                                        iTextSharp.text.Image itextImage = iTextSharp.text.Image.GetInstance(bitmap, System.Drawing.Imaging.ImageFormat.Bmp);
                                        itextImage.ScalePercent(72.0f / itextImage.DpiX * 100);
                                        itextImage.SetAbsolutePosition(0.0f, 0.0f);
                                        contentByte.AddImage(itextImage);
                                        iTextDocument.NewPage();
                                    }
                                }
                            }
                        }
                    }

Open in new window

2
 

Author Closing Comment

by:Euless_Tech
ID: 41857730
Thanks guys. Appreciate the quick response.
0

Featured Post

3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Today I had a very interesting conundrum that had to get solved quickly. Needless to say, it wasn't resolved quickly because when we needed it we were very rushed, but as soon as the conference call was over and I took a step back I saw the correct …
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
This Micro Tutorial will teach you how to censor certain areas of your screen. The example in this video will show a little boy's face being blurred. This will be demonstrated using Adobe Premiere Pro CS6.
This Micro Tutorial will give you a basic overview how to record your screen with Microsoft Expression Encoder. This program is still free and open for the public to download. This will be demonstrated using Microsoft Expression Encoder 4.

776 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question