C # Unit Converter's graphic code detailed introduction

This article is mainly for you to introduce in detail the C # Unit converter simple case, a simple WinForm application, with a certain reference value, interested in small partners can refer to

After several days of study, wrote a simple WinForm application, put out the source code, in case of a rainy day.

After the software is launched, the interface looks like this:

, the program consists of 6 labels, 8 combobox, 8 textbox, and 4 button. The right 4 textbox sets the ReadOnly property to True.

When the software starts, you can let the ComboBox display the default entries, you need to use the Combobox.selectedindex statement, by default, combobox.selectedindex= "-1" (that is, no items are displayed by default), and 1 to 0 to display the first item. Put the code in the form's Load event. code example:

private void Mainform_load (object sender, EventArgs e)  {   combobox1.selectedindex = 0;   Combobox2.selectedindex = 1;   Combobox3.selectedindex = 0;   Combobox4.selectedindex = 1;   Combobox5.selectedindex = 0;   Combobox6.selectedindex = 1;   Combobox7.selectedindex = 0;   Combobox8.selectedindex = 1;  }

Press the OK button, execute the conversion function, convert the result to a string type, and assign it to TextBox.Text, code instance:

  private void Button4_Click (object sender, EventArgs e) {string str1, str2;   Str1=convert.tostring (Combobox7.selecteditem);   Str2=convert.tostring (Combobox8.selecteditem);   Double D1, D2;    if (Textbox7.text = = "") {Textbox7.text = "1";   D1 = 1;   } else D1 = convert.todouble (textbox7.text);    if (str1 = = str2) {d2 = D1;   Textbox8.text = convert.tostring (D2);     } else {if (str1 = = "Celsius" && str2 = = "Fahrenheit") {d2=1.8*d1+32;    Textbox8.text = convert.tostring (D2);     } if (str1 = = "degree Celsius" && str2 = = "Kelvin") {d2=d1+273.15;    Textbox8.text = convert.tostring (D2);     } if (str1 = = "Fahrenheit" && str2 = = "Celsius") {d2= (d1-32)/1.8;    Textbox8.text = convert.tostring (D2);     } if (str1 = = "Fahrenheit" && str2 = = "Kelvin") {d2= (d1-32)/1.8+273.15;    Textbox8.text = convert.tostring (D2);     } if (str1 = = "Kelvin" && str2 = = "Celsius") {d2 = d1-273.15;   Textbox8.text = convert.tostring (D2); } if (str1 = = "Kelvin" && str2 = = "Fahrenheit") {D2 = (d1-273.15) * 1.8 + 32;    Textbox8.text = convert.tostring (D2); }   }  }

Prevents the input box from entering keys other than backspace, numeric, and decimal (the temperature conversion can enter a minus sign), preventing the user from entering non-numeric characters to make the program error. Add the relevant code in the KeyPress event, code example:

  private void Textbox1_keypress (object sender, KeyPressEventArgs e)  {   if (e.keychar! = ' \b ' && e.keychar!) = 46)//Allow input of backspace and decimal key   {    if (E.keychar < ' 0 ') | | (E.keychar > ' 9 ')) Allow input 0-9 number     {     e.handled = true;    }   }   }