SelectCommand.Connection property has not been initialized.

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this code for class connection

C#

public class myConnection
   {
       public SqlConnection con;
       public void GetConnection()
       {

           string str = "Data Source=HEND-PC;Initial Catalog=f_library;Integrated Security=True";
           SqlConnection con = new SqlConnection(str);
           con.Open();

       }
   }

this is for form

C#

public partial class Form1 : Form
    {
        myConnection cnn = new myConnection();
        
        public Form1()
        {
           
            InitializeComponent();
         


        }

        private void button1_Click(object sender, EventArgs e)
        {
          
            cnn.GetConnection();
            
            SqlDataAdapter dad = new SqlDataAdapter("Select * from emp where emp_fname='" + txt_name.Text + "'and emp_lname='" + txt_lname.Text + "' ", cnn.con);
             DataSet ds = new DataSet();
            dad.Fill(ds);
            if (ds.Tables[0].Rows.Count > 0)
            {
                
                dataGridView1.DataSource = ds.Tables[0];
            }
            else
            {
                  MessageBox.Show("conn is failed");                
            }

Posted 15-Sep-14 21:56pm

iceprincess50

Updated 15-Sep-14 21:59pm

v2

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George Jonsson · Answer 1 · 2014-09-15T22:03:00

Change the method GetConnection to this.
Remove the variable declaration of SqlConnection inside the method.

C#

public class myConnection
{
    // This construct auto creates a property.
    // You can use this in your code as a regular property
    // private set means that you can only give a value to the property inside this class
    public SqlConnection con { get; private set; }

    public void GetConnection()
    {
        string str = "Data Source=HEND-PC;Initial Catalog=f_library;Integrated Security=True";
        SqlConnection con = new SqlConnection(str);
        con = new SqlConnection(str);
        con.Open();   
    }
}

iceprincess50 · Answer 2 · 2014-09-15T22:12:00

Solution 2

thnx
but i try u code the same error

Posted 15-Sep-14 22:12pm

iceprincess50

Comments

George Jonsson 16-Sep-14 4:15am

Don't post comments as an answer.

iceprincess50 · Answer 3 · 2014-09-15T22:21:00

C#

public class myConnection
{
    public SqlConnection con { get; private set; } // Don't use public variables
    public void GetConnection()
    {
 
        string str = "Data Source=HEND-PC;Initial Catalog=f_library;Integrated Security=True";
        SqlConnection con = new SqlConnection(str);
        con = new SqlConnection(str);
        con.Open();
    
    }
}

how to make {get; private set;}!?

SelectCommand.Connection property has not been initialized.

3 solutions

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