What do you mean by "send the directory"? Do you mean pass the String containing the folder path from one form to another? This question has been asked and answered many times. Passing data from one form to another is the same passing data from any object to any other object. Forms are just objects after all.
To pass data into an object you need to either set a property or call a method and pass a parameter. As i said, this goes for forms too, as they are just objects. You need to declare a property or method in your second form that will accept a String and then pass it on internally to wherever it needs to go. If this form is ALWAYS going to need this path then the logical thing to do is to make this property or method the constructor. A constructor is a method named after the type and is executed when you use the "new" key word, e.g.
CSharp Code:
public partial class Form2 : Form
{
public Form2(string path)
{
InitializeComponent();
// Use path here as required.
}
}
Now when you create the form you pass it the path from the TextBox:
CSharp Code:
Form2 f2 = new Form2(this.TextBox1.Text);