Why does not this work on my user control?

Question

Why does not this work on my user control?

Navigation

#1 by (3 votes)

0

I have a code that would like to put it in the user control of my windows forms, but it does not make changes to Form1, what's the reason?

Code:

private void button5_Click(object sender, EventArgs e)
{
    Form1 f1 = new Form1();
    var tab = new TabPage();
    var aba = new Abas();
    tab.Text = "Guia " + ((int)f1.tabControl1.TabCount + 1).ToString();
    f1.tabControl1.TabPages.Add(tab);
    tab.Controls.Add(aba);
    f1.tabControl1.SelectTab(tab);
    aba.Dock = DockStyle.Fill;
}

If I put this code in a button of Form1 itself, it works normally.

c# winforms

asked by anonymous 18.05.2017 / 00:37

1 answer

Insert ScrollView throughout Activity How to change page in Ionic V2

score 3 · Accepted Answer

Since you open Form1 , inside it you have a command that opens Form2 , and in Form2 , a button to add tabPage to Form1 , the code should look like this :

Form1.cs:

 //Evento que abre o Form2
 private void buttonAbrirForm2_Click(object sender, EventArgs e)
 {
     Form2 form = new Form2();
     form.Parent = this;
     form.Show();
 }

Form2.cs:

 //Evento que adiciona a tab no Form1
 private void buttonAddTabForm1_Click(object sender, EventArgs e)
 {
    Form1 f1 = ((Form1)this.Parent);
    var tab = new TabPage();
    var aba = new Abas();
    tab.Text = "Guia " + ((int)f1.tabControl1.TabCount + 1).ToString();
    f1.tabControl1.TabPages.Add(tab);
    tab.Controls.Add(aba);
    f1.tabControl1.SelectTab(tab);
    aba.Dock = DockStyle.Fill;

 }

There is still no way to pass Form1 to Parent of Form2 , and from anywhere in the application you access Form1 :

    private void buttonAddTabForm1_Click(object sender, EventArgs e)
    {
        foreach (Form f in Application.OpenForms)
        {
            if (f is Form1)
            {
                 Form1 f1 = ((Form1)f);
                 var tab = new TabPage();
                 var aba = new Abas();
                 tab.Text = "Guia " + ((int)f1.tabControl1.TabCount +1).ToString();
                 f1.tabControl1.TabPages.Add(tab);
                 tab.Controls.Add(aba);
                 f1.tabControl1.SelectTab(tab);
                 aba.Dock = DockStyle.Fill;
                break;
            }
        }

    }

As I said in the comments, I believe this is not the situation for creating a custom userControl. But anyway I made one that changes Form1, and here it worked perfectly:

Example:

    //Evento do botão que está dentro do userControl1
    private void button1_Click(object sender, EventArgs e)
    {
        if (this.Parent is Form1)
        {
            ((Form1)this.Parent).Text = "Texto foi alterado pelo controle";
        }
    }

In the case of your Control:

private void button5_Click(object sender, EventArgs e)
{
    if (this.Parent is Form1)
    {
        Form1 f1 = ((Form1)this.Parent);
        var tab = new TabPage();
        var aba = new Abas();
        tab.Text = "Guia " + ((int)f1.tabControl1.TabCount + 1).ToString();
        f1.tabControl1.TabPages.Add(tab);
        tab.Controls.Add(aba);
        f1.tabControl1.SelectTab(tab);
        aba.Dock = DockStyle.Fill;
    }
}

Note: In order for you to access controls outside the form, the modifiers property must be set to public