How to add query in a Datagridview?

Question

I managed to make Inserts and Updates.

I downloaded this file:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MySql.Data.MySqlClient;
using System.Data;

namespace MySQLClass
{

//Don't forget to add the MySQL.Data dll to your projects references
//It can be downloaded for free from MySQL's official website.
//Link to the .NET Connector (MS Installer) http://dev.mysql.com/downloads/connector/net/


class MySQLClient
{
    MySqlConnection conn = null;


    #region Constructors
    public MySQLClient(string hostname, string database, string username, string password)
    {
        conn = new MySqlConnection("host=" + hostname + ";database=" + database +";username=" + username +";password=" + password +";");
    }

    public MySQLClient(string hostname, string database, string username, string password, int portNumber)
    {
        conn = new MySqlConnection("host=" + hostname + ";database=" + database + ";username=" + username + ";password=" + password + ";port=" + portNumber.ToString() +";");
    }

    public MySQLClient(string hostname, string database, string username, string password, int portNumber, int connectionTimeout)
    {
        conn = new MySqlConnection("host=" + hostname + ";database=" + database + ";username=" + username + ";password=" + password + ";port=" + portNumber.ToString() + ";Connection Timeout=" + connectionTimeout.ToString() +";");
    }
    #endregion

    #region Open/Close Connection
    private bool Open()
    {
        //This opens temporary connection
        try
        {
            conn.Open();
            return true;
        }
        catch
        {
            //Here you could add a message box or something like that so you know if there were an error.
            return false;
        }
    }

    private bool Close()
    {
        //This method closes the open connection
        try
        {
            conn.Close();
            return true;
        }
        catch
        {
            return false;
        }
    }
    #endregion

    public void Insert(string table, string column, string value)
    {
        //Insert values into the database.

        //Example: INSERT INTO names (name, age) VALUES('John Smith', '33')
        //Code: MySQLClient.Insert("names", "name, age", "'John Smith, '33'");
        string query = "INSERT INTO " + table + " (" + column + ") VALUES (" + value + ")";

        try
        {
            if (this.Open())
            {
                //Opens a connection, if succefull; run the query and then close the connection.

                MySqlCommand cmd = new MySqlCommand(query, conn);

                cmd.ExecuteNonQuery();
                this.Close();
            }
        }
        catch { }
        return;
    }

    public void Update(string table, string SET, string WHERE)
    {
        //Update existing values in the database.

        //Example: UPDATE names SET name='Joe', age='22' WHERE name='John Smith'
        //Code: MySQLClient.Update("names", "name='Joe', age='22'", "name='John Smith'");
        string query = "UPDATE " + table + " SET " + SET + " WHERE " + WHERE + "";

        if (this.Open())
        {
            try
            {
                //Opens a connection, if succefull; run the query and then close the connection.

                MySqlCommand cmd = new MySqlCommand(query, conn);
                cmd.ExecuteNonQuery();
                this.Close();
            }
            catch { this.Close(); }
        }
        return;
    }

    public void Delete(string table, string WHERE) 
    {
        //Removes an entry from the database.

        //Example: DELETE FROM names WHERE name='John Smith'
        //Code: MySQLClient.Delete("names", "name='John Smith'");
        string query = "DELETE FROM " + table + " WHERE " + WHERE + "";

        if (this.Open())
        {
            try
            {
                //Opens a connection, if succefull; run the query and then close the connection.

                MySqlCommand cmd = new MySqlCommand(query, conn);
                cmd.ExecuteNonQuery();
                this.Close();
            }
            catch { this.Close(); }
        }
        return;
    }

    public Dictionary<string, string> Select(string table, string WHERE)
    {
        //This methods selects from the database, it retrieves data from it.
        //You must make a dictionary to use this since it both saves the column
        //and the value. i.e. "age" and "33" so you can easily search for values.

        //Example: SELECT * FROM names WHERE name='John Smith'
        // This example would retrieve all data about the entry with the name "John Smith"

        //Code = Dictionary<string, string> myDictionary = Select("names", "name='John Smith'");
        //This code creates a dictionary and fills it with info from the database.

        string query = "SELECT * FROM " + table + " WHERE " + WHERE + "";

        Dictionary<string, string> selectResult = new Dictionary<string, string>();

        if (this.Open())
        {
            MySqlCommand cmd = new MySqlCommand(query, conn);
            MySqlDataReader dataReader = cmd.ExecuteReader();

            try
            {
                while (dataReader.Read())
                {

                    for (int i = 0; i < dataReader.FieldCount; i++)
                    {
                        selectResult.Add(dataReader.GetName(i).ToString(), dataReader.GetValue(i).ToString());
                    }

                }
                dataReader.Close();
            }
            catch { }
            this.Close();

            return selectResult;
        }
        else
        {
            return selectResult;
        }
    }

    public int Count(string table)
    {
        //This counts the numbers of entries in a table and returns it as an integear

        //Example: SELECT Count(*) FROM names
        //Code: int myInt = MySQLClient.Count("names");

        string query = "SELECT Count(*) FROM " + table + "";
        int Count = -1;
        if (this.Open() == true)
        {
            try
            {
                MySqlCommand cmd = new MySqlCommand(query, conn);
                Count = int.Parse(cmd.ExecuteScalar() + "");
                this.Close();
            }
            catch { this.Close(); }
            return Count;
        }
        else
        {
            return Count;
        }
    }

}
}

I happen to be trying to make a query, that can place on a datagridView, but that function is not done. Are there any files that recommend me in addition to this one? Or what can I add here so you can do something like:

dataGridView1=Mysql.query("Select * from tabela");

Answer 1

Opa, since you already have the class ready and with connection already made, just add this method in your Mysqlclient class

public DataTable ExecuteDataTable(string Query)
{
    MySqlCommand cmd = new MySqlCommand(Query, conn);
    MySqlDataAdapter da = new MySqlDataAdapter();
    DataTable dt = new DataTable();
    try
    {
        cmd.CommandType = CommandType.Text;
        da.SelectCommand = cmd;
        da.Fill(dt);
        return dt;
    }
    catch (Exception ex)
    {
        throw new Exception(ex.Message);
    }
    finally
    {
        cmd.Connection.Close();
        cmd.Dispose();
    }
}

And then call it that (in your scenario):

dataGridView1.DataSource = Mysql.ExecuteDataTable("Select * from tabela"); //Popular o grid
dataGridView1.DataBind(); //explodir na tela