How to get value from column of Database to variable

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My Database has 3 column are "Name", "Math", "Chemistry" and "Sum". I can query some rows by SQL in C#, but I don't know how to get the value from column to variable in C#. If anyone know, please help me!

For ex:

C#

SqlConnection con;
SqlCommand cm1;
DataSet ds;
SqlDataAdapter ap;

private void btn_info_Click(object sender, EventArgs e)
{
    cm1 = new SqlCommand("SELECT * FROM Database ", con);

    ap = new SqlDataAdapter(cm1);
    ds = new System.Data.DataSet();
    ap.Fill(ds, "Database");
    DataGridView1.DataSource = ds.Tables[0];
    DataGridView1.DisplayMember = "Math";
}

My Database has 7 rows, so that column "Math" has 7 values are {10, 5.5, 6, 7.5, 9, 8, 8.5}.
I use the query "SELECT * FROM Database".
After that, How can I get the value of Math column to an array or a variable?

Posted 24-Dec-15 20:31pm

Member 12035413

Updated 24-Dec-15 21:04pm

v2

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Comments

Tomas Takac 25-Dec-15 2:38am

You need to show your code. Use Improve question to update your question.

2 solutions

Solution 2

C#

private void btn_info_Click(object sender, EventArgs e)
   
SqlConnection con;
SqlCommand cm1;
DataSet ds;
SqlDataAdapter ap;
 {
        cm1 = new SqlCommand("SELECT * FROM Database ", con);

        ap = new SqlDataAdapter(cm1);
        ap.Fill(ds);
        DataGridView1.DataSource = ds;
        DataGridView1.DataBind();
    }

Posted 25-Dec-15 2:09am

Arasappan

Updated 25-Dec-15 2:10am

v2

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OriginalGriff · Accepted Answer · 2015-12-24T23:14:00

Well, you already have it in a collection - the DataTable that you filled and used as the data source for the DataGridView - so I'd probably access the values from that.
Try this:

C#

DataTable dt = ds.Tables[0];
double[] mathValues = new double[dt.Rows.Count];
int index = 0;
foreach (DataRow row in dt.Rows)
   {
   mathValues[index++] = (double) row["Math"];
   }