How can I display data in the data grid view by selecting my database table in my combo box? I am struggling to display the specific data from the table selected in the combo box. This is on c# and MySQL.

here is my code:

private void samples_Load(object sender, EventArgs e)
{
    MySqlConnection con = new MySqlConnection(conn);
    try
    {
        con.Open();
        MySqlCommand sqlCmd = new MySqlCommand();

        sqlCmd.Connection = con;
        sqlCmd.CommandType = CommandType.Text;

        sqlCmd.CommandText = "select table_name from information_schema.tables where table_schema = 'attenddb'";

        MySqlDataAdapter sqlDataAdap = new MySqlDataAdapter(sqlCmd);

        DataTable dtRecord = new DataTable();
        sqlDataAdap.Fill(dtRecord);
        comboBox1.DataSource = dtRecord;
        comboBox1.DisplayMember = "TABLE_NAME";
        con.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

private void button1_Click(object sender, EventArgs e)
{
    try
    {
        string query2 = "select table_name from ['"  comboBox1.Text   "']";
        MySqlConnection con2 = new MySqlConnection(conn);
        MySqlCommand com2 = new MySqlCommand(query2, con2);
        MySqlDataAdapter myadapt = new MySqlDataAdapter();
        myadapt.SelectCommand = com2;
        DataTable dtable = new DataTable();
        myadapt.Fill(dtable);
        dataGridView1.DataSource = dtable;
    }
    catch
    {
        MessageBox.Show("Error Loading data");
    }
}

CodePudding user response：

Don't use Bracket [] and single quotes.

string query2 = "select columnname from "   comboBox1.Text  "";

CodePudding user response：

You must select all the columns with * from the selected table.

string query2 = "select * from ["  comboBox1.Text   "]";

or with string interpolation:

string query2 = $"select * from [{comboBox1.Text}]";

And also, do not use single quotes around the table name (you already have the square brackets), since you want the name directly and not as string literal.