The easiest -and not recommended- way to do it is to concatenate the text
to the query:

string strOleDb = "Select * from ProjectTable WHERE (ProjectName LIKE '" +
textBox1.Text + "')";

  This would work, BUT it has the risk of suffering what is known as a "Sql
Injection attack": If a user enters in the textbox something that looks like
Sql, it would be executed at your server. It also has other problems, for
instance, if the Text were "O'Donell", the code would crash with a syntax
error due to the single quote.

   The recommended way to pass the text is to parameterize the Sql Query:

string strOleDb = "Select * from ProjectTable WHERE (ProjectName LIKE ?)";
OleDbCommand cmd = new OleDbCommand(strOleDb, connection);
cmd.Parameters.AddWithValue("FirstParam", textBox1.Text);