Tell me more ×
Stack Overflow is a question and answer site for professional and enthusiast programmers. It's 100% free, no registration required.
up vote 0 down vote favorite

we have a value in our database that is numeric we take through the database and then we want to insert it to another value but we want it to be converted to DOUBLE from Numeric

So any ideas how can we convert our Numeric variable to double ?

edit

Database = Microsoft SQL Server Database File (SqlClient) (.mdf)

double point = 0;


cn.Open();
point = Convert.ToDouble("select bounty from provider where sirname = '" + globals2.stringena + "' ");
cn.close();

bounty = Numeric(18,2)

so want to pass this value to my point variable.

The error i get is

Input string was not in a correct format.

share|improve this question
What database? SQL, Access, etc? – Tim 15 hours ago
Could you please add code snippet that you use for getting you numeric value from database. – Alexey Aza 15 hours ago
ok i put code so you can see what i wanna do. – Dimitris B 15 hours ago
So you already know how to convert a C# decimal value to double: you can use Convert.ToDouble. Is your question really "How do I retrieve a value from the database?"? – hvd 15 hours ago
1  
Convert.ToDouble will only convert strings which have only digits and/or a period. If the value you want to convert is already a number try casting it directly, put (Double) in front of it. – tinstaafl 15 hours ago
show 1 more comment

2 Answers

up vote 1 down vote 
string query = "select bounty from provider where sirname = @name";
double numericToDouble = 0;
using (SqlConnection con = new SqlConnection(YourDB.ConnectionString)
{
    using(SqlCommand cmd = new SqlCommand(query,con))
    {
        cmd.Parameters.AddWithValue(@name,"nameYouNeed");
        try{
          con.Open();
          SqlDataReader reader = cmd.ExecuteReader();
          if (reader.Read())
             numericToDouble = Convert.ToDouble32(reader[0].ToString());
          con.Close();
        }
        catch(SqlError someError)
        {
           MessageBox.Show(someError.Message);
        }
    } 
}

Note: the @name is a parameter that we need to pass to the query at runtime. so I created an sql command that uses the query and connect to the DB. when the new command is create it passes the value of @name, if you see the line "cmd.parameters...." after that it reads from the DB, and check if it succeeded to read something, if so it convert the value to string and then to double. I assumed that the numeric field is the first column in your table. If it's not you can change the code FROM: 

numericToDouble = Convert.ToDouble32(reader[0].ToString());

TO:

numericToDouble = Convert.ToDouble32(reader["NameOfTheNumericField"].ToString());

Hope this will help you..

share|improve this answer
2  
I dont think a method exist like Convert.ToDouble32. – Sriram Sakthivel 14 hours ago
you can actually do reader.GetSqlDecimal(0).ToDouble() to avoid error-prone string parsing. – rgripper 14 hours ago
@SriramSakthivel msdn.microsoft.com/en-us/library/ayes1wa5.aspx it exists in .NET 4.5 – Elior 13 hours ago
@Elior the link you provided above also doesn't show any method named Convert.ToDouble32. Method name is Convert.ToDouble in which one of the overload takes parameter System.Int32. – Sriram Sakthivel 9 hours ago
up vote -1 down vote

you have to convert to double, then you multiple with 100 (if you want only 2 decimals) and store it like int! When you loaded from the DB you have just to divide with 100!

an old member of to4ari.gr

or just use the float type....

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.