如何在C＃中从子窗体调用父窗体方法？

Question

I have a parent form with 1 method to refresh the panel content called resetPanel() . I also have a button in the parent form. If I click the button, a new form opens up. I will do some changes and click on save. The content gets saved in the database and the child form closes. Now the parent form will be displayed.

I want to call the resetPanel() method now, so that the panel shows the updated values. How can I achieve this?

Answer 1

If your child form is a dialog one, you can just check the form's dialog result :

// Do not forget to release resources acquired: 
// wrap IDisposable into using(..) {...}
using (Form myChildForm = new MyChildForm()) {
  //TODO: If you want to pass something from the main form to child one: do it

  // On any result save "Cancel" update the panel
  if (myChildForm.ShowDialog() != DialogResult.Cancel) 
    resetPanel();
}

In case your child from is not a dialog you can pass this into child form as reference to main one:

  Form myChildForm = new MyChildForm(this);

  myChildForm.Show(); // <- Just show, not ShowDialog()

  ...

  private MyMainForm m_MainForm;

  public MyChildForm(MyMainForm form) {
    m_MainForm = form;
  }

  private void save() {
    //TODO: Save to database here

    // Main form update
    if (!Object.ReferenceEquals(null, m_MainForm))
      m_MainForm.resetPanel(); // <- resetPanel should be public or internal method
  }

  private saveButton_Click(object sender, EventArgs e) {
    save();
  }

Answer 2

After you close your Form2 , you can call the ResetPanel method:

Form2 f2 = new Form2();
f2.ShowDialog();
resetPanel();  // <-- this will be executed when you close the second form

Answer 3

for Eg ur Parent Form Name If form Form1 and child Form Name as Form2 goto ur Child form Designer page Change it Access Modifier as Public

and from what ever method you want Call

Form2 f2=new Form2();
f2.Show();
.//from here on you can write your concerned code

Answer 4

If your resetPanel method is doing a database call, you quite possibly can avoid it. Although this will not get any data that was being updated by another user in your application. Just modified code from another answer of mine for your needs. This is just a sample:

public class ParentForm : Form
{
    Button openButton = new Button();

    public ParentForm()
    {
        openButton.Click += openButton_Click;
    }

    void openButton_Click(object sender, EventArgs e)
    {
        ChildForm childForm = new ChildForm();
        childForm.OKButtonClick += childForm_OKButtonClick;
        childForm.ShowDialog();
    }

    void childForm_OKButtonClick(object sender, MyEventArgs e)
    {
        // Use properties from event args and set data in this form
    }

}

public class ChildForm : Form
{
    Button okButton = new Button();
    TextBox name = new TextBox();
    TextBox address = new TextBox();

    public event EventHandler<MyEventArgs> OKButtonClick;

    public ChildForm()
    {
        okButton.Click += okButton_Click;
    }

    void okButton_Click(object sender, EventArgs e)
    {
        try
        {
            bool saveSucceeded = false;

            // Try saving data here

            if (saveSucceeded)
            {
                if (OKButtonClick != null)
                {
                    MyEventArgs myEventArgs = new MyEventArgs();

                    // Just get updated data from screen and send it to another form
                    myEventArgs.Name = name.Text;
                    myEventArgs.Address = address.Text;

                    OKButtonClick(sender, myEventArgs);
                }

                Close();
            }
            else
            {
                MessageBox.Show("Data could not be saved.");
            }
        }
        catch (Exception ex)
        {
            // Perform proper exception handling
        }
    }
}

public class MyEventArgs : EventArgs
{
    public string Name
    {
        get;
        set;
    }

    public string Address
    {
        get;
        set;
    }
}

Answer 5

Try to set the Save button in your child Form to DialogResult.Ok and then make the Save button as the AcceptButton for child Form. And then test if the result if it the user press that Save Button. Programmatically it could look like this:

Form2 chidForm = new Form2();
childForm.btnSave.DialogResult = DialogResult.Ok
childForm.AcceptButton = childForm.btnSave
if (childForm.ShowDialog() == DialogResult.Ok)
{
  resetPanel();
}

Now, I assume here that your Save button in Child Form is named btnSave .