Develop Reference

How can I create a button with a dropdown arrow near it?

I did :
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Test
{
public partial class Form1 : Form
{
private int x, y;
private int gap = 0;
private int startingY = 83;
private GroupBox lastGB = null;
public Form1()
{
InitializeComponent();
button1.Text = "Details " + char.ConvertFromUtf32(8595);
}
The result is something bad not looking good :
This is what I want to make : The NEW is acting like a button it is a button. The arrow near it is like a combobox :
If I click on the NEW it will open folder dialog if I click on the arrow it will open kind of combobox without the borders.

This is called SplitButton. This question has been asked few times over the years.
You can draw an inspiration from the Windows Forms codebase.
Or look at other answers to the same question: Split button in .NET Winforms.
Or search online for SplitButton.

Missing reference for wpf window? .Show() missing along with other display functions

I am working on an Outlook 2016 VSTO plugin and I'd like to add a WPF window display functionality to a button. So now my code looks something like this :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Tools.Ribbon;
using System.Windows.Forms;
using System.Windows.Forms.Integration;
using System.Windows;
namespace TaskManager
{
public partial class RibbonTaskManager
{
private void RibbonTaskManager_Load(object sender, RibbonUIEventArgs e)
{
}
private void ButtonAddGroups_Click(object sender, RibbonControlEventArgs e)
{
FormAddGroups formAddGroups = new FormAddGroups();
formAddGroups.Show();
}
}
}
The problem is that apparently formAddGroups does not contain a definition for "Show". I tried looking for possible missing references to no avail.
I added
System.xaml
WindowsFormsIntegration
PresentationCore
PresentationFramework
I also found this thread, but the accepted answer solves a different problem, I think.

You can't call Show() on a UserControl but could create a window and set its Content property to an instance of your UserControl:
var window = new System.Windows.Window();
window.Content = new FormAddGroups();
win.Show();

C# smooth resize of the form (smooth resize efect)

First of all, beginner here, apologies in advance if my question has obvious answer, but until now, I didn't manage to figure it out.
So, I'm trying to make an Windows Form App. In this app I have two forms: the login form and main window form. To make it look more "fancy", after successfully logging in, the main window form must increase its size (same size as the login form) to something bigger. I managed to create the code I need, but the resize effect looks "laggy". Is there a way to make this smother? Or is there another way to make the resize of the form smoother?
PS. I have set the "FormBorderStyle" property to "None"
Bellow, my code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace SlindingPanel
{
public partial class MainWindow : Form
{
public MainWindow()
{
InitializeComponent();
// Enables the timer
timer1.Enabled = true;
}
private void timer1_Tick(object sender, EventArgs e)
{
if (this.Width >= 820 && this.Height >= 540) this.timer1.Enabled = false;
else {
// Resizes the form
this.ClientSize = new System.Drawing.Size(Width + 20, Height + 20);
//Centers the form on the screen
this.CenterToScreen();
}
}
}

This may be late, but I suggest using the "anchor" attribute of the UI controls.

How to use event handlers in C#

I created a form with just 2 textboxes and a button. In the first one I type a temperature in Fahrenheit and when I press the button "Convert", the program calculates and puts the temperature in Celsius in the other TextBox. It's working fine.
Now I want the program to clear the second TextBox when I start typing in the first TextBox. Below I show just a part of the code, which didn't work. Can anybody help me?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Conv_Temp
{
public partial class Frm_Principal : Form
{
public Frm_Principal()
{
InitializeComponent();
}
public event EventHandler Leave;
private void Tb_Temp_Leave(object sender, EventArgs e)
{
MessageBox.Show("Leaving TB Tb_Temp");
Tb_Result.Text="";
}
}
}

I think you are almost there.
Try adding this under InitializeComponent();
this.Tb_Temp.TextChanged += new System.EventHandler(this.Tb_Temp_Leave);

Add new Event handler in your form designer code.
this.textBox1.TextChanged += new System.EventHandler(this.ModifyTextBox1);
and implement this event in above form.cs file(Form_Principal )
private void ModifyTextBox1(object sender, EventArgs e)
{
textBox2.Text = String.Empty;
}
Please follow good convention for writing codes this is just a demo.

C# Multiple Forms and Panels

I have a Main Screen form set up, with it's body consisting of one giant panel. I then have a series of User Controls which get erased or loaded into that Main Screen. What I don't know how to do is have the User Controls affect the Main Screen.
Code Example from a User Control:
PartsSystem parts = new PartsSystem(); //a user control
MainMenu.pnlMain.Controls.Clear();
MainMenu.pnlMain.Controls.Add(parts);
This code works when loading the main screen, but I can't seem to access pnlMain from my other user controls. Is it possible to fix this? I have a function set up to grab a user Control within the MainMenu form, but I can't seem to get it to be called from a user control. I'm trying to make it so that when they click a button, they go to the next screen (user control).
I am using C# on Windows 7 with Visual Studio 2010 and all the default settings.
Here is some additional code samples:
public partial class Main_Menu : Form
{
public Main_Menu()
{
InitializeComponent();
MainMenuPanel main = new MainMenuPanel();
panelChange(main);
}
public void panelChange(UserControl newPanel)
{
pnlMain.Controls.Clear();
pnlMain.Controls.Add(newPanel);
}
}
That was Main_Menu. This code works on launch. Now, bringing up my PartsSystem is another issue.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace Program_v1._0._0._0._4
{
public partial class MainMenuPanel : UserControl
{
public MainMenuPanel()
{
InitializeComponent();
Main_Menu parentForm = (this.Parent as Main_Menu);
}
public void btnPartsInventory_Click(object sender, EventArgs e)
{
Main_Menu myParent = (this.Parent as Main_Menu);
PartsSystem parts = new PartsSystem();
myParent.pnlMain.Controls.Clear(); //Object reference not set to an instance of an object.
//This is the error I get at this point. It won't let me use the function.
myParent.pnlMain.Controls.Add(parts);
}
}
}
Thank you for the help!

Try using UserControl.Parent to get access the parent control.
access form from usercontrol
Get access to parent control from user control - C#