So I have 2 Forms:
Form1
Form2
There is a button on Form2, that I'd like to have hide Form1 when clicked.
Button Click from Button in Form2
var mainFrm = new Form1();
mainFrm.Hide();
This does nothing. I'm obviously missing something, but can't seem to figure it out.
Any help is definitely appreciated!
If your form1 is already present in the page, then why do you need to initialize it again? Just set the visible status to false to hide it.
mainFrm.Visible = false;
without seeing more of the code it's hard to answer, but you definitely need to reference the the old Form1 that is already visible and hide it. You are creating a new form and hiding it.
You have to define your Form2 class to store the reference to the main form.
public partial class Form2 : Form
{
/* reference to the main form will be stored here */
private Form1 _mainForm;
public Form2(Form1 mainForm)
{
InitializeComponent();
/* Initialize the main form field */
this._mainForm = mainForm;
}
private void button1_Click(object sender, EventArgs e)
{
/* Set the main form visibility to false */
_mainForm.Visible = false;
}
}
Now when you are creating the Form2 instance just add the main form to the constructor:
/* Show the form2 */
_form2 = new Form2(this);
_form2.Show();
Note: this will refer to the form that creates the Form2 object.
You could create a static form type property in your Form1 and set it when Form1 is Shown, and then use it to hide your form
Here is a code that worked for me.
private void button1_Click(object sender, EventArgs e)
{
var objForm1 = new Form1();
Form1.Fom1ref = objForm1;
objForm1.Show();
}
private void button2_Click(object sender, EventArgs e)
{
Form1.Fom1ref.Hide();
}
Here is the property that should be set in Form1.
public static Form Fom1ref { get; set; }
Related
I have 2 forms each with buttons, textboxes, and labels. In form1 I have a this code in a button event handler:
frmTwo form = new frmTwo ();
form.Show();
this.Visible = false; //closing form 1 when frmTwo opens
I went to the designer file for frmTwo and changed all of the controls: labels, textboxes, buttons from private (which was auto generated) to public.
Under this line of code: this.Visible = false; I want to put an if statement to check if a name textbox in frmTwo is blank. But when I write txtName.Text it says the textbox doesn't exist in the current context. I understand why it doesn't exist because its inside frmTwo NOT from1. But I'm not sure what other ways I can access this textbox because I already made it public in the designer. Is there another way to do this?
Ask yourself: Is it important for form1 that the information that you want to read from form2 is in a textbox? Would form1 really care if the same information would be kept by form2 in a ComboBox?
Wouldn't it be best if form1 doesn't know how form2 gets the information? All it has to know is that form2 is willing to provide the information. If form2 needs to read it from a database, or fetch it from the internet to fetch the information, why would form1 care? All form1 wants to know: "Hey Form2, give me information X"
Alas you didn't tell us if you want this information only once, or that form1 needs to be kept informed whenever information X changes. Let's assume that you do.
So, class Form2 will have a method to provide information X, and it is willing to tell everyone that information X is changed. Form2 does not show to the outside world how it gets its information. The current version holds information X in the text of TextBox1. Future versions might read it from a ComboBox, or read if from a file, or from the internet.
class Form2 : System.Windows.Window
{
public event EventHandler XChanged;
public string X
{
// information X is in textBox1
get => this.textBox1.Text;
}
private void TextBox1_Changed(object sender, ...)
{
// the text in textBox1 changed, so information X changed
this.OnXChanged();
}
protected virtual void OnXChanged()
{
this.XChanged?.Invoke(new Eventhandler(this, EventArgs.Empty));
}
... // other Form2 methods
}
Now if Form1 wants to know the value of X, it can simply ask for it:
Form2 form2 = ...
string informationX = form2.X;
If Form1 wants to be kept informed whenever information X changes:
form2.XChanged += InformationXChanged;
private void InformationXChanged(object sender, Eventargs e)
{
Form2 form2 = (Form2)sender;
// get the new information X from form2:
string informationX = form2.X;
this.ProcessInformationX(informationX);
}
If you want one form to replace the other, then you pass a reference to Form1 in the .Show() of Form2 and the form stores it in the .Owner property. The when the second form starts it will hide the first form. Additionally, when the second form closes it can unhide the first form.
Please use Capitalized names for types like Form and pascalCase for variables like mainForm = new Form().
Form1.cs
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
var f2 = new Form2();
f2.Show(this);
}
}
Form2.cs
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
this.FormClosing += Form2_FormClosing;
this.Owner.Visible = false;
}
private void Form2_FormClosing(object sender, FormClosingEventArgs e)
{
Owner.Visible = true;
}
public bool IsNameBlank { get => string.IsNullOrWhiteSpace(textBox1.Text); }
}
This is the basic framework. I also added some logic where Form1 checks for a textBox in Form2. Add a property in Form2 that returns the check:
and access it form From1
private void button1_Click(object sender, EventArgs e)
{
var f2 = new Form2();
f2.Show(this);
if (f2.IsNameBlank)
{
// textBox is empty.
}
}
I have two forms. First, Form1 has a group box, some labels and a listbox. I press a button and new Form2 is opened and contains some text. I want to transfer the text in Form2 to the listbox in the Form1.
So far, what I have done is make modifier of listbox to public and then put this code in the button of Form2
Form1 frm = new Form1();
frm.ListBox.items.Add(textBox.Text);
But amazingly, this does not add any value. I thought I was mistaken with the insertion so I made the same procedure. This time, I made a label public and added textbox value to its Text property but it failed.
Any ideas?
Try adding a parameter to the constructor of the second form (in your example, Form1) and passing the value that way. Once InitializeComponent() is called you can then add the parameter to the listbox as a choice.
public Form1(String customItem)
{
InitializeComponent();
this.myListBox.Items.Add(customItem);
}
// In the original form's code:
Form1 frm = new Form1(this.textBox.Text);
Let's assume Form1 calls Form2. Please look at the code:
Form1:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Show();
frm.VisibleChanged += formVisibleChanged;
}
private void formVisibleChanged(object sender, EventArgs e)
{
Form2 frm = (Form2)sender;
if (!frm.Visible)
{
this.listBox1.Items.Add(frm.ReturnText);
frm.Dispose();
}
}
}
Form2:
public partial class Form2 : Form
{
public string ReturnText { get; set; }
public Form2()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
this.ReturnText = this.textBox1.Text;
this.Visible = false;
}
}
The answer is to declare public property on Form2 and when form gets hidden. Access the same instance and retrieve the value.
Below code working perfect on my machine.
private void button1_Click(object sender, EventArgs e)
{
Form1 f1 = new Form1();
f1.listBox1.Items.Add(textBox1.Text );//ListBox1 : Modifier property made public
f1.ShowDialog();
}
Ok, If you are Calling Sequence is like, Form1->Form2 and Form2 updates the value of Form1 then you have to use ParentForm() or Delegate to update the previous form.
Form1 frm = new Form1();
frm is now a new instance of class Form1.
frm does not refer to the original instance of Form1 that was displayed to the user.
One solution is, when creating the instance of Form2, pass it a reference to your current instance of Form1.
Please avoid the concept of making any public members like you said
>>i have done is make modifier of listbox to public and then in form2 in button code<<
this is not a good practice,on the other hand the good one is in Brad Christie's Post,I hope you got it.
This code will be inside the form containing myListBox probably inside a button click handler.
Form2 frm2 = new Form2();
frm2.ShowDialog();
this.myListBox.Items.Add(frm2.myTextBox.Text);
frm2.Dispose();
I am making this simple Windows forms app in Visual studio in c#. I have two forms. On form1 I have a textbox,listbox and two buttons (one to insert into listbox from textbox and another to open form2). On form2 I only have a textbox. I just simply want, when click on a button (for opening form2) on form1, form2 to open and textbox to contain (on formLoad) selected item from listbox from form1. But when I click on button it says "Object reference not set to an instance of an object". What am I doing wrong? I am pretty sure it's something simple but I just can't get it.
Thanks in advance!
Here is my code:
on form1:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btnOpenForm2_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2();
f2.ShowDialog();
}
private void button1_Click(object sender, EventArgs e)
{
listBox1.Items.Add(textBox1.Text);
}
public string Transfer
{
get { return listBox1.SelectedItem.ToString(); }
}
and on form2:
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private void Form2_Load(object sender, EventArgs e)
{
Form1 f1 = new Form1();
textBox1.Text = f1.Transfer;
}
Because in the Form2_Load event you always create a new instance of Form1 and then access the Transfer property which accesses listBox1.SelectedItem which is not set for the newly created form.
You should rather pass a referece to form 1 in the button event:
on form1:
private void btnOpenForm2_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2(this);
f2.ShowDialog();
}
and on form2:
public partial class Form2 : Form
{
Form1 f1;
public Form2(Form1 f1)
{
this.f1 = f1;
InitializeComponent();
}
private void Form2_Load(object sender, EventArgs e)
{
textBox1.Text = this.f1.Transfer;
}
}
In your Form2_Load method, you're creating a new instance of the object Form1, separate from your existing item.
Instead, you need to either:
a) Pass a reference to your current Form1 object to Form2, so that Form2 can access the Transfer property.
or b) Add a new property to Form2 (called Transfer, say), and then when you create Form2, assign the current textbox value to this property, like so:
Form2 f2 = new Form2();
f2.Transfer = listBox1.SelectedItem.ToString();
f2.ShowDialog();
You could also do this by adding a parameter to the constructor of Form2, although that's really a design decision.
because you haven't selected your listbox item,value listBox1.SelectedItem is null.Practice doing try catch block
You are creating new Form1 instance here, which is not related to Form1 instance which you used to open Form2:
private void Form2_Load(object sender, EventArgs e)
{
Form1 f1 = new Form1(); // here is new instance of Form1 created
textBox1.Text = f1.Transfer;
}
So, this new Form1 instance does not have selected item and you have error. I suggest you to pass selected item value to Form2 when you opening Form2:
private void btnOpenForm2_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2(Transfer); // pass selected item value to constructor
f2.ShowDialog();
}
All you need is changing Form2 constructor to accept this string:
public Form2(string transfer)
{
InitializeComponent();
textBox1.Text = transfer;
}
I'm trying to use chart to show some graphics.
I have two Forms (Form1 and Form2 ).The chart is located in Form2, but I want to write the code in Form1, like let's say in Form1 when I click on GRAPHIC button will show me chart in Form2.
The problem is when I write the code in Form1, it give me error saying the name of the chart(which is found in Form2) not found in Form1. How can I solve this problem.
This is part of my code:
private void button2_Click(object sender, EventArgs e) // Graphic
{
Form2 fr2 = new Form2(A );
this.Hide();
fr2.ShowDialog();
chart1.series["student's grad"].Points.Addxy("A", A);
}
You can try this
public Form2(object A)
{
InitializeComponent();
chart1.series["student's grad"].Points.Addxy("A", A);
}
A couple things that I can see, the first is that you are using ShowDialog which will run fr2 as a Modal Dialog box which will Block Form1 until you close fr2, the second is that since you are wanting to access the Chart in frm2 you would either need to use a Public Property/Method or make your Chart's Visibility Public. I would recommend that you use a Property or a Public Method that way you are keeping the internals of your second Form Hidden.
Something like this might work for you:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Form2 fr2 = new Form2();
this.Hide();
fr2.AddPoint("student's grad", new Point( 0,0));
fr2.ShowDialog();
}
}
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
public void AddPoint( string series, Point chartPoint)
{
chart1.Series["student's grad"].Points.AddXY(chartPoint.X, chartPoint.Y);
}
}
So I want basically the user to login in first in order to use the other form. However, my dilemma is that the login box is in Form2, and the main form is Form1.
if ((struseremail.Equals(username)) && (strpasswd.Equals(password)))
{
MessageBox.Show("Logged in");
form1.Visible = true;
form1.WindowState = FormWindowState.Maximized;
}
else
{
MessageBox.Show("Wow, how did you screw this one up?");
}
However, Form1 doesn't become visible, (since I launch it as visble = false) after they log in. Can someone help?
EDIT:
Brilliant response, but my problem is still here. I basically want to load Form2 First, (which is easy I run Form1 and set it to hide) But when Form2 is closed, I want Form1 to be closed as well.
private void Form2_FormClosing(Object sender, FormClosingEventArgs e)
{
Form1 form1 = new Form1();
form1.Close();
MessageBox.Show("Closing");
}
this doesn't seem to work...
You will need to pass the reference of one form to another, so that it can be used in the other form. Here I've given an example of how two different forms can communicate with each other. This example modifies the text of a Label in one form from another form.
Download Link for Sample Project
//Your Form1
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Form2 frm = new Form2(this);
frm.Show();
}
public string LabelText
{
get { return Lbl.Text; }
set { Lbl.Text = value; }
}
}
//Your Form2
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private Form1 mainForm = null;
public Form2(Form callingForm)
{
mainForm = callingForm as Form1;
InitializeComponent();
}
private void Form2_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
this.mainForm.LabelText = txtMessage.Text;
}
//Added later, closing Form1 when Form2 is closed.
private void Form2_FormClosed(object sender, FormClosedEventArgs e)
{
mainForm.Close();
}
}
(source: ruchitsurati.net)
(source: ruchitsurati.net)
When you log in and do Form1.visible = true; have you also tried Form1.Show(); that should show form2
However, Personally, I would prefer setting the application to run form2 directly in the program.cs file.
static void Main()
{
Application.Run(new Form2());
}
then when user successfully logs in, do
form1.Show();
this.Hide(); // this part is up to you
mind you, in form2, when / after you instantiate form1, you might want to also add this :
newform1.FormClosed += delegate(System.Object o, FormClosedEventArgs earg)
{ this.Close(); };
this closes form2 when form1 is closed
better yet do form1.Show() in a new thread, and then this.Close(); for form2. this removes the need of adding to the form2's FormClosed event: you can thus close form2 immediately after starting form1 in a new thread. But working with threads might get a little complicated.
EDIT:
form2 is form1's parent. if form2 is your main application form, closing it closes your program (generally). Thus you either want to just hide and disable form2, and close it only after form1 is closed, or start form1 in a new thread. Your edit pretty much opens form1, then immediately closes it.