c# - What am I doing wrong on the decimal button, seems my bool is off? -

i not understand doing incorrectly in dotbutton, shows not give correct results? advise?

public partial class form1 : form     {         public form1()         {             initializecomponent();         }         private bool isfirst = true;         private bool shouldclear = true;         private double num1;         private double num2;         private double result = 0;         private string symbol = string.empty;         private bool hasdecimal = false;          private void numberbutton_click(object sender, eventargs e)         {             button sourcebutton = (sender button);             double oldnumber, buttonnumber, newnumber;              if (shouldclear)             {                 outputtextbox.clear();                 oldnumber = 0;                 shouldclear = false;             }             else             {                 oldnumber = double.parse(outputtextbox.text);                 hasdecimal = true;             }              buttonnumber = double.parse(sourcebutton.text);             newnumber = (oldnumber * 10) + buttonnumber;              if (isfirst)             {                 num1 = newnumber;             }             else             {                 num2 = newnumber;             }             outputtextbox.text += sourcebutton.text;             calculate(symbol);         }         private void calculate(string operatorsymbol)         {             if (isfirst)             {                 result = num1;                 return;             }             switch (operatorsymbol)             {                 case "+":                     result = num1 + num2;                     break;                 case "-":                     result = num1 - num2;                     break;                 case "*":                     result = num1 * num2;                     break;                 case "/":                     result = num1 / num2;                     break;             }         }         private void operatorbutton_click(object sender, eventargs e)         {             num1 = result;              button sourcebutton = (sender button);             string operatorsymbol = sourcebutton.text;              if (isfirst)                 isfirst = false;              hasdecimal = true;             shouldclear = true;             symbol = operatorsymbol;             outputtextbox.text = result.tostring();          }          private void equalsbutton_click(object sender, eventargs e)         {             outputtextbox.text = result.tostring();             isfirst = true;             shouldclear = true;             hasdecimal = true;         }          private void clearbutton_click(object sender, eventargs e)         {             outputtextbox.text = "0";             result = 0;             isfirst = true;             shouldclear = true;             hasdecimal = false;         }          private void dotbutton_click(object sender, eventargs e)         {             if (hasdecimal)                 hasdecimal = true;             isfirst = false;             shouldclear = true;             outputtextbox.text = dotbutton.text;             }         }     }   namespace windowsformsapplication2 {     partial class form1     {         /// <summary>         /// required designer variable.         /// </summary>         private system.componentmodel.icontainer components = null;          /// <summary>         /// clean resources being used.         /// </summary>         /// <param name="disposing">true if managed resources should disposed; otherwise, false.</param>         protected override void dispose(bool disposing)         {             if (disposing && (components != null))             {                 components.dispose();             }             base.dispose(disposing);         }          #region windows form designer generated code          /// <summary>         /// required method designer support - not modify         /// contents of method code editor.         /// </summary>         private void initializecomponent()         {             this.zerobutton = new system.windows.forms.button();             this.onebutton = new system.windows.forms.button();             this.twobutton = new system.windows.forms.button();             this.threebutton = new system.windows.forms.button();             this.fourbutton = new system.windows.forms.button();             this.fivebutton = new system.windows.forms.button();             this.sixbutton = new system.windows.forms.button();             this.sevenbutton = new system.windows.forms.button();             this.eightbutton = new system.windows.forms.button();             this.ninebutton = new system.windows.forms.button();             this.dotbutton = new system.windows.forms.button();             this.addbutton = new system.windows.forms.button();             this.subtractbutton = new system.windows.forms.button();             this.multiplybutton = new system.windows.forms.button();             this.dividebutton = new system.windows.forms.button();             this.clearbutton = new system.windows.forms.button();             this.equalsbutton = new system.windows.forms.button();             this.outputtextbox = new system.windows.forms.textbox();             this.suspendlayout();             //              // zerobutton             //              this.zerobutton.location = new system.drawing.point(9, 230);             this.zerobutton.margin = new system.windows.forms.padding(2);             this.zerobutton.name = "zerobutton";             this.zerobutton.size = new system.drawing.size(58, 41);             this.zerobutton.tabindex = 0;             this.zerobutton.text = "0";             this.zerobutton.usevisualstylebackcolor = true;             this.zerobutton.click += new system.eventhandler(this.numberbutton_click);             //              // onebutton             //              this.onebutton.location = new system.drawing.point(9, 184);             this.onebutton.margin = new system.windows.forms.padding(2);             this.onebutton.name = "onebutton";             this.onebutton.size = new system.drawing.size(38, 41);             this.onebutton.tabindex = 1;             this.onebutton.text = "1";             this.onebutton.usevisualstylebackcolor = true;             this.onebutton.click += new system.eventhandler(this.numberbutton_click);             //              // twobutton             //              this.twobutton.location = new system.drawing.point(51, 184);             this.twobutton.margin = new system.windows.forms.padding(2);             this.twobutton.name = "twobutton";             this.twobutton.size = new system.drawing.size(38, 41);             this.twobutton.tabindex = 2;             this.twobutton.text = "2";             this.twobutton.usevisualstylebackcolor = true;             this.twobutton.click += new system.eventhandler(this.numberbutton_click);             //              // threebutton             //              this.threebutton.location = new system.drawing.point(93, 184);             this.threebutton.margin = new system.windows.forms.padding(2);             this.threebutton.name = "threebutton";             this.threebutton.size = new system.drawing.size(38, 41);             this.threebutton.tabindex = 3;             this.threebutton.text = "3";             this.threebutton.usevisualstylebackcolor = true;             this.threebutton.click += new system.eventhandler(this.numberbutton_click);             //              // fourbutton             //              this.fourbutton.location = new system.drawing.point(9, 139);             this.fourbutton.margin = new system.windows.forms.padding(2);             this.fourbutton.name = "fourbutton";             this.fourbutton.size = new system.drawing.size(38, 41);             this.fourbutton.tabindex = 4;             this.fourbutton.text = "4";             this.fourbutton.usevisualstylebackcolor = true;             this.fourbutton.click += new system.eventhandler(this.numberbutton_click);             //              // fivebutton             //              this.fivebutton.location = new system.drawing.point(51, 139);             this.fivebutton.margin = new system.windows.forms.padding(2);             this.fivebutton.name = "fivebutton";             this.fivebutton.size = new system.drawing.size(38, 41);             this.fivebutton.tabindex = 5;             this.fivebutton.text = "5";             this.fivebutton.usevisualstylebackcolor = true;             this.fivebutton.click += new system.eventhandler(this.numberbutton_click);             //              // sixbutton             //              this.sixbutton.location = new system.drawing.point(93, 139);             this.sixbutton.margin = new system.windows.forms.padding(2);             this.sixbutton.name = "sixbutton";             this.sixbutton.size = new system.drawing.size(38, 41);             this.sixbutton.tabindex = 6;             this.sixbutton.text = "6";             this.sixbutton.usevisualstylebackcolor = true;             this.sixbutton.click += new system.eventhandler(this.numberbutton_click);             //              // sevenbutton             //              this.sevenbutton.location = new system.drawing.point(9, 93);             this.sevenbutton.margin = new system.windows.forms.padding(2);             this.sevenbutton.name = "sevenbutton";             this.sevenbutton.size = new system.drawing.size(38, 41);             this.sevenbutton.tabindex = 7;             this.sevenbutton.text = "7";             this.sevenbutton.usevisualstylebackcolor = true;             this.sevenbutton.click += new system.eventhandler(this.numberbutton_click);             //              // eightbutton             //              this.eightbutton.location = new system.drawing.point(51, 93);             this.eightbutton.margin = new system.windows.forms.padding(2);             this.eightbutton.name = "eightbutton";             this.eightbutton.size = new system.drawing.size(38, 41);             this.eightbutton.tabindex = 8;             this.eightbutton.text = "8";             this.eightbutton.usevisualstylebackcolor = true;             this.eightbutton.click += new system.eventhandler(this.numberbutton_click);             //              // ninebutton             //              this.ninebutton.location = new system.drawing.point(93, 93);             this.ninebutton.margin = new system.windows.forms.padding(2);             this.ninebutton.name = "ninebutton";             this.ninebutton.size = new system.drawing.size(38, 41);             this.ninebutton.tabindex = 9;             this.ninebutton.text = "9";             this.ninebutton.usevisualstylebackcolor = true;             this.ninebutton.click += new system.eventhandler(this.numberbutton_click);             //              // dotbutton             //              this.dotbutton.location = new system.drawing.point(72, 230);             this.dotbutton.margin = new system.windows.forms.padding(2);             this.dotbutton.name = "dotbutton";             this.dotbutton.size = new system.drawing.size(58, 41);             this.dotbutton.tabindex = 10;             this.dotbutton.text = ".";             this.dotbutton.usevisualstylebackcolor = true;             this.dotbutton.click += new system.eventhandler(this.dotbutton_click);             //              // addbutton             //              this.addbutton.location = new system.drawing.point(135, 230);             this.addbutton.margin = new system.windows.forms.padding(2);             this.addbutton.name = "addbutton";             this.addbutton.size = new system.drawing.size(38, 41);             this.addbutton.tabindex = 11;             this.addbutton.text = "+";             this.addbutton.usevisualstylebackcolor = true;             this.addbutton.click += new system.eventhandler(this.operatorbutton_click);             //              // subtractbutton             //              this.subtractbutton.location = new system.drawing.point(135, 184);             this.subtractbutton.margin = new system.windows.forms.padding(2);             this.subtractbutton.name = "subtractbutton";             this.subtractbutton.size = new system.drawing.size(38, 41);             this.subtractbutton.tabindex = 12;             this.subtractbutton.text = "-";             this.subtractbutton.usevisualstylebackcolor = true;             this.subtractbutton.click += new system.eventhandler(this.operatorbutton_click);             //              // multiplybutton             //              this.multiplybutton.location = new system.drawing.point(135, 139);             this.multiplybutton.margin = new system.windows.forms.padding(2);             this.multiplybutton.name = "multiplybutton";             this.multiplybutton.size = new system.drawing.size(38, 41);             this.multiplybutton.tabindex = 13;             this.multiplybutton.text = "*";             this.multiplybutton.usevisualstylebackcolor = true;             this.multiplybutton.click += new system.eventhandler(this.operatorbutton_click);             //              // dividebutton             //              this.dividebutton.location = new system.drawing.point(135, 93);             this.dividebutton.margin = new system.windows.forms.padding(2);             this.dividebutton.name = "dividebutton";             this.dividebutton.size = new system.drawing.size(38, 41);             this.dividebutton.tabindex = 14;             this.dividebutton.text = "/";             this.dividebutton.usevisualstylebackcolor = true;             this.dividebutton.click += new system.eventhandler(this.operatorbutton_click);             //              // clearbutton             //              this.clearbutton.location = new system.drawing.point(9, 48);             this.clearbutton.margin = new system.windows.forms.padding(2);             this.clearbutton.name = "clearbutton";             this.clearbutton.size = new system.drawing.size(80, 41);             this.clearbutton.tabindex = 15;             this.clearbutton.text = "clear";             this.clearbutton.usevisualstylebackcolor = true;             this.clearbutton.click += new system.eventhandler(this.clearbutton_click);             //              // equalsbutton             //              this.equalsbutton.location = new system.drawing.point(93, 48);             this.equalsbutton.margin = new system.windows.forms.padding(2);             this.equalsbutton.name = "equalsbutton";             this.equalsbutton.size = new system.drawing.size(80, 41);             this.equalsbutton.tabindex = 16;             this.equalsbutton.text = "=";             this.equalsbutton.usevisualstylebackcolor = true;             this.equalsbutton.click += new system.eventhandler(this.equalsbutton_click);             //              // outputtextbox             //              this.outputtextbox.location = new system.drawing.point(9, 3);             this.outputtextbox.margin = new system.windows.forms.padding(2);             this.outputtextbox.multiline = true;             this.outputtextbox.name = "outputtextbox";             this.outputtextbox.size = new system.drawing.size(164, 41);             this.outputtextbox.tabindex = 17;             //              // form1             //              this.autoscaledimensions = new system.drawing.sizef(6f, 13f);             this.autoscalemode = system.windows.forms.autoscalemode.font;             this.clientsize = new system.drawing.size(184, 280);             this.controls.add(this.outputtextbox);             this.controls.add(this.equalsbutton);             this.controls.add(this.clearbutton);             this.controls.add(this.dividebutton);             this.controls.add(this.multiplybutton);             this.controls.add(this.subtractbutton);             this.controls.add(this.addbutton);             this.controls.add(this.dotbutton);             this.controls.add(this.ninebutton);             this.controls.add(this.eightbutton);             this.controls.add(this.sevenbutton);             this.controls.add(this.sixbutton);             this.controls.add(this.fivebutton);             this.controls.add(this.fourbutton);             this.controls.add(this.threebutton);             this.controls.add(this.twobutton);             this.controls.add(this.onebutton);             this.controls.add(this.zerobutton);             this.margin = new system.windows.forms.padding(2);             this.name = "form1";             this.text = "form1";             this.resumelayout(false);             this.performlayout();          }          #endregion          private system.windows.forms.button zerobutton;         private system.windows.forms.button onebutton;         private system.windows.forms.button twobutton;         private system.windows.forms.button threebutton;         private system.windows.forms.button fourbutton;         private system.windows.forms.button fivebutton;         private system.windows.forms.button sixbutton;         private system.windows.forms.button sevenbutton;         private system.windows.forms.button eightbutton;         private system.windows.forms.button ninebutton;         private system.windows.forms.button dotbutton;         private system.windows.forms.button addbutton;         private system.windows.forms.button subtractbutton;         private system.windows.forms.button multiplybutton;         private system.windows.forms.button dividebutton;         private system.windows.forms.button clearbutton;         private system.windows.forms.button equalsbutton;         private system.windows.forms.textbox outputtextbox;     } } 

i suspect want

outputtextbox.text += dotbutton.text; 

(you missed +)