You have to explain a little bit more, like what is your input and what shall be your output? What kind of type is your tblGameBindingSource ? A SQL-Datasource?
maybe like this?
string tmp = textBox.Text;
string filterString = string.Format("[Platform] LIKE '%{0}%' OR [Game Title] LIKE '%{0}%'",tmp);
this.tblGameBindingSource.Filter = filterString;
But if you code like this you have to take care of sql injections .