Rework using parameterized queries C#

Question

There is a lot of tutorials regarding parameterized queries but most of them involve using SqlCommand, the only thing my code accepts is SqlDataAdapter for my SQL command, anytime I try to instantiate it as a SqlCommand I get errors.

TL;DR
I either need guidance on how to rework this using parameterized queries or I need to know why my SqlDataAdapter line doesn't work as an SqlCommand line.

private void btnLogin_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\Jake\Documents\Data.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True;");

    SqlDataAdapter sda = new SqlDataAdapter("Select Count(*) From Login Where Username = '" + txtUsername.Text + "' and Password = '" + txtPassword.Text + "'", con);
    DataTable dt = new DataTable();
    sda.Fill(dt);

    if (dt.Rows[0][0].ToString() == "1")
    {
        this.Hide();
        MessageBox.Show("LOGIN!");
    }
    else
    {
        MessageBox.Show("FAILED!");
    }
}

Answer 1

You can use Parameters.AddWithValue in SqlDataAdapter

    sda.SelectCommand.Parameters.AddWithValue("@ParamName",value);

Check this: c# Using Parameters.AddWithValue in SqlDataAdapter