C# Foreach with MySQL

Question

I am currently working on a patching system in C# and I have came across a small complication. I am using MySQL to store an archive for my update list. The patching system then detects the version of program, and downloads every patch after that version. Though I just started learning how to use MySQL in C# so i'm not sure how to do, or call a lot of the functions needed. What I want to do is use foreach to call all values in the "version" column/row, then use a while loop to check against current version and new version until they are the same. I just cant seem to figure out how to use the two together and can't find any references.

using (SqlCon = new MySqlConnection(connString))
{
    SqlCon.Open();
    string command = "SELECT * FROM version ORDER BY version";
    MySqlCommand GetLatestVersion = new MySqlCommand(command, SqlCon);

    using (MySqlDataReader DR = GetLatestVersion.ExecuteReader())
    {
        while (DR.Read())
        {
            foreach(DataTable i in DR)
            {
                while(v1 < v2)
                {
                    string LatestVersion = Convert.ToString(DR.GetValue(1));
                    string WebURL = Convert.ToString(DR.GetValue(2));
                    update.DownloadProgressChanged += new DownloadProgressChangedEventHandler(download);
                    update.DownloadFileCompleted += new AsyncCompletedEventHandler(extration);
                    update.DownloadFileAsync(new Uri(WebURL), tempFilePath + "patch" + Latest_Version + ".zip");
                }
            }
        }
    }
}
SqlCon.Close();

I would greatly appreciate any help.

esskar · Accepted Answer · 2011-11-30 13:53:11Z

3

just remove the inner foreach and you are good to go.

answered Nov 30, 2011 at 13:53

esskar

11k3 gold badges38 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Tim Coker · Accepted Answer · 2011-11-30 14:02:13Z

1

First thing is you don't need the SqlCon.Close(); at the end. At the end of the using block, the object is disposed of (the point of a using block).

You can modify your select statement to only select versions greater than your program's current version. This way, any records selected should be processed/downloaded. (I put the version in quotes in the SQL statement below because your code indicates that it's a string. You're probably better off specifying this value as numeric for sorting/comparison purposes, though.)

//for readability, I changed the variable name to myProgramsVersion

using (SqlCon = new MySqlConnection(connString))
{
    SqlCon.Open();
    string command = "SELECT * FROM version where version > '" + myProgramsVersion + "' ORDER BY version";
    MySqlCommand GetLatestVersion = new MySqlCommand(command, SqlCon);

    using (MySqlDataReader DR = GetLatestVersion.ExecuteReader())
    {
        while (DR.Read())
        {
            string LatestVersion = Convert.ToString(DR.GetValue(1));
            string WebURL = Convert.ToString(DR.GetValue(2));
            update.DownloadProgressChanged += new DownloadProgressChangedEventHandler(download);
            update.DownloadFileCompleted += new AsyncCompletedEventHandler(extration);
            update.DownloadFileAsync(new Uri(WebURL), tempFilePath + "patch" + Latest_Version + ".zip");
        }
    }
}

answered Nov 30, 2011 at 14:02

Tim Coker

6,5242 gold badges34 silver badges65 bronze badges

3 Comments

dpg199200 Over a year ago

I actually never had tried to use greater than or less than signs in an sql query. I didn't know it was possible or I would of done that instead of trying to do the for loop. I'm using the assembly version to check against the database. I was going to use the file version, but when i try it say it's to long to be converted into Version(); I got one last question if you don't mind me asking. Is it possible to check against the assembly version of another program? I found how to check the file version with FileVersionInfo, but i does no good when i can't get the value with an error

Tim Coker Over a year ago

I assume you're talking about the major/minor/build/revision numbers. You could create for separate columns in the database for each then load them into a Version object and use its CompareTo() method. That would preclude my suggestion offered above (unless you want to write a REALLY messy SQL statement). Another option is to convert the assembly version to an integer as specified in the question linked at the end of this comment. You can store this in the database and do a simple > on integers. As that question points out, though, this isn't foolproof. bit.ly/sCyL6

dpg199200 Over a year ago

Ah ok well I got it figured out. Now just need to figure out how to get the program to only process one thing at a time. It keeps trying to process everything at once.

Collectives™ on Stack Overflow

C# Foreach with MySQL

2 Answers 2

Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related