You need to pass the value of the text box on form 1 to form 2 so form 2 can use it to get the dataset.
I think you need to do something like this (using the "constructor approach" from the article i suggested)
http://www.codeproject.com/Articles/14122/Passing-Data-Between-Forms
private void button1_Click(object sender, System.EventArgs e)
{
Form2 frm=new Form2(entmatno.Text);
frm.Show();
}
String entmatno = "";
public string Entmatno
{
set { entmatno = value; }
get { return entmatno; }
}
public Form2(string entmatnoFromForm1)
{
InitializeComponent();
Entmatno=entmatnoFromForm1);
}
private void Resultpage_Load(object sender, EventArgs e)
{
this.COURSEINFO_TBLTableAdapter.Fill(this.CourseInfoDataSet.COURSEINFO_TBL, Entmatno);
this.reportViewer1.RefreshReport();
}