Hello Everyone,
I have three forms, Form1, Form2 and Form3. Form3 runs first and has a button that when clicked runs Form 1 and a webBrowser window. Form1 has two buttons. When one is clicked it runs Form2 and the other button calls a function in Form3. Form2 has two buttons, one runs Form3 and the other calls a function in Form3. However when I run the code I get an error 'NullReferenceException was unhandled - Object reference not set to an instance of an object' when I click one of the buttons to call a function in Form3. I have included the code for each Form below. does anyone have any ideas as to why I am obtaining a NullReferenceException?
Thanks in advance
SubProf
Form1 Code:
namespace FunctionCalls
{
public partial class Form1 : Form
{
public Form3 win2;
public Form3 act3;
public string res1;
public string res2;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
res1 = "onetwo";
res2 = "threefour";
Form2 win4 = new Form2(res1, res2, win2);
win4.win3 = this;
win4.ShowDialog();
}
private void button2_Click(object sender, EventArgs e)
{
act3.Form3Function();
//act3 is null when code runs
}
}
}
Form2 code:
namespace FunctionCalls
{
public partial class Form2 : Form
{
public Form1 win3;
public Form3 fr3;
public string ans1;
public string ans2;
public Form2(string res3, string res4, Form3 f3)
{
ans1 = res3;
ans2 = res4;
fr3 = f3;
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(ans1);
fr3.webBrowser1.Navigate("http://www.bbc.co.uk");
//fr3 is null when code runs
}
private void button2_Click(object sender, EventArgs e)
{
Form3 frm6 = new Form3();
frm6.Show(this);
}
}
}
Form3 code:
namespace FunctionCalls
{
public partial class Form3 : Form
{
public Form2 win5;
public Form3()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Form1 frm1 = new Form1();
frm1.Show(this);
}
public void Form3Function()
{
MessageBox.Show("Form3 Function Called From Form2");
}
}
}
