C # how to access the methods and variables in the parent form using the winform subform

This is suddenly used in today's work, but I have never touched it before! However, with the help of experienced colleagues, the problem was quickly solved. You can use the following methods:

1. When a child form object is constructed in the parent form, the parent form is passed over:

For example, FrmSub frm = new FrmSub (this); // this indicates the parent form

2. Change the variables and methods to be accessed in the parent form to public.

3. Define the global variable of a parent form in the child form class:

For example, private dynamic m_parentContainer; // you can use dynamic to dynamically identify the type of the variable.

4. Add reference Microsoft. CSharp. dll

5. directly use m_parentContainer. variable name or m_parentContainer. method name for access.

If (m_ParentContainer.mFrm2BaseLibDataEdite = null | m_ParentContainer.mFrm2BaseLibDataEdite.IsDisposed) // mFrm2BaseLibDataEdite is the parent form variable
{
M_ParentContainer.mFrm2BaseLibDataEdite = new frm2BaseLibDataEdite ();
If (m_ParentContainer.mFrm2BaseLibDataEdite.IsDisposed = false)
{
M_ParentContainer.fnAddChildFormToMDIForm (m_ParentContainer.mFrm2BaseLibDataEdite); // fnAddChildFormToMDIForm () is the parent form Method
M_ParentContainer.mFrm2BaseLibDataEdite.Show ();
}
}
Else {
M_ParentContainer.mFrm2BaseLibDataEdite.WindowState = FormWindowState. Maximized;
M_ParentContainer.mFrm2BaseLibDataEdite.Activate ();
M_ParentContainer.mFrm2BaseLibDataEdite.Show ();
}