Get Sql query result with datareader.C#

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Hello everyone,

Im trying to fill some textboxes with values from a database table.when i write a name in a textbox,i use it as a parameter for the query,the query result should show the values in different textboxes,for example the surname in one textbox,the id in another etc.Is there any way to do this??

im not english,so i hope u understand me.

here is part of my code,the part where i check if enter is pressed,connect to the db,below are 3 ways for datareader but none of them shows anything:

C#

private void CheckKeys(object sender, System.Windows.Forms.KeyPressEventArgs e)
        {
            string _connString = String.Format(System.Globalization.CultureInfo.InvariantCulture,
            @"Data Source = {0}\SQL_CE.sdf", Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase));
            SqlCeConnection _connection = new SqlCeConnection(_connString);

            

            if (e.KeyChar == (char)13)
            {

                SqlCeCommand command = new SqlCeCommand("SELECT surname, ID FROM Data where name=@name;", _connection);
                
                command.Parameters.Add("@name", txt_name.Text);

                _connection.Open();
                SqlCeDataReader rdr = command.ExecuteReader();
                    
                if(rdr.Read())
                {
     
                    txt_surname.Text=Convert.IsDBNull(rdr["Surname"]) ? "" : Convert.ToString(rdr["Surname "]);
                    txt_ID.Text = rdr["ID"].ToString();

                    }
                    rdr.Close();

                }

Posted 12-Mar-12 5:13am

IviKAZAZI

Updated 13-Jul-17 5:42am

v2

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Herman<T>.Instance 12-Mar-12 11:17am

what have you tried? Please show your code and show where you are stuck. In that way we can help you.

2 solutions

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OriginalGriff · Accepted Answer · 2012-03-12T05:27:00

Solution 1

This isn't the exact code, but it is a starting point. All the bits you need are there.

C#

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT description FROM myTable WHERE ID=@ID", con))
        {
        cmd.Parameters.AddWithValue("@ID", myId);
        using (SqlDataReader reader = cmd.ExecuteReader())
            {
            while (reader.Read())
                {
                string desc = (string) reader["description"];
                Console.WriteLine("ID: {0}\n    {1}", myId, desc);
                }
            }
        }
    }

Posted 12-Mar-12 5:27am

OriginalGriff

Comments

IviKAZAZI 12-Mar-12 11:29am

i want to get multiple values,and set them in different textboxes

OriginalGriff 12-Mar-12 11:50am

The code you have added shows you retrieving two items from a row and saving them to different TextBoxes.
However, I can't guarantee that it will fetch anything.
First off, don't use "magic numbers" like "(char)13" - use system names if possible. In this case it is: Keys.Return is the value you should be testing against.
Secondly, it depends where you have your event handler hooked, and where the user input cursor is.
If you are handling it for the form, then it will not occur when the cursor is in the TextBox unless the "KeyPreview" property of the Form is set to "true".
Have you tried putting a breakpoint on the _connString declaration line and stepping through your code?

Ganesan Senthilvel · Accepted Answer · 2012-03-12T05:30:00

Here is the sample code:

C#

this.textBoxName.KeyPress += new System.Windows.Forms.KeyPressEventHandler(CheckKeys);


private void CheckKeys(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
 if (e.KeyChar == (char)13)
 {
   // Then Enter key was pressed
   string ConnectionString = "server=xxx;userid=aaa;"+ "pwd=bbb;database=northwind";
   con = new SqlConnection(ConnectionString);
   con.Open();
  string CommandText = "SELECT SurName" +
                       "  FROM Employees" +
                       " WHERE (Name LIKE @)" + textBoxName.Text;
  cmd = new SqlCommand(CommandText);
  rdr = cmd.ExecuteReader();
  while(rdr.Read())
  {
     textSurName = rdr["SurName"].ToString()
  }
 }
}