How to keep a value in text box after adding a decimal point

Question

Hi I am struggling to keep a value in my calculator's text box when I add a decimal point to a number and then want to add another number after the decimal point. Here is my code: What code must I add to keep the value in the text box after I added a decimal point? Thank you!

public Form1()
        {
            InitializeComponent();
        }

        double total1 = 0;
        double total2 = 0;
        bool plusButtonClicked = false;
        bool subtractButtonClicked = false;
        bool multiplyButtonClicked = false;
        bool divideButtonClicked = false;

        private void btnSeven_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnSeven.Text;

        }

        private void btnNine_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnNine.Text;
        }

        private void btnEquals_Click(object sender, EventArgs e)
        {
            if (plusButtonClicked == true)
            {
                total2 = total1 + double.Parse(txtDisplay.Text);
            }
            else if (subtractButtonClicked == true)
            {
                total2 = total1 - double.Parse(txtDisplay.Text);
            }
            else if (multiplyButtonClicked == true)
            {
                total2 = total1 * double.Parse(txtDisplay.Text);
            }
            else if (divideButtonClicked == true)
            {
                total2 = total1 / double.Parse(txtDisplay.Text);
            }
            {
                txtDisplay.Text = total2.ToString();
                total1 = 0;
            }

        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            total1 = total1 + double.Parse(txtDisplay.Text);
            txtDisplay.Clear();


            plusButtonClicked = true;
            subtractButtonClicked = false;
            multiplyButtonClicked = false;
            divideButtonClicked = false;
        }

        private void btnOne_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnOne.Text;

        }

        private void btnTwo_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnTwo.Text;
        }

        private void btnThree_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnThree.Text;
        }

        private void btnFour_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnFour.Text;
        }

        private void btnFive_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnFive.Text;
        }

        private void btnSix_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnSix.Text;
        }

        private void btnEight_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnEight.Text;
        }

        private void btnPoint_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = txtDisplay.Text + btnPoint.Text;
        }

        private void btnZero_Click(object sender, EventArgs e)
        {
            txtDisplay.Text = btnZero.Text;
        }


        private void btnSubtract_Click(object sender, EventArgs e)
        {
            total1 = total1 + double.Parse(txtDisplay.Text);
            txtDisplay.Clear();


            plusButtonClicked = false;
            subtractButtonClicked = true;
            multiplyButtonClicked = false;
            divideButtonClicked = false;
        }

        private void btnMultiply_Click(object sender, EventArgs e)
        {
            total1 = total1 + double.Parse(txtDisplay.Text);
            txtDisplay.Clear();


            plusButtonClicked = false;
            subtractButtonClicked = false;
            multiplyButtonClicked = true;
            divideButtonClicked = false;
        }

        private void btnDivide_Click(object sender, EventArgs e)
        {
            total1 = total1 + double.Parse(txtDisplay.Text);
            txtDisplay.Clear();


            plusButtonClicked = false;
            subtractButtonClicked = false;
            multiplyButtonClicked = false;
            divideButtonClicked = true;
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtDisplay.Clear();
        }

    }
}

Answer 1

The issue seems to be that you are doing this:

private void some_button_Click(object sender, EventArgs e)
{
    txtDisplay.Text = btnEight.Text;
}

So, if you click 4 , and then . it'll show 4. , but when you click 5 , it'll set it to 5 .

You need to add to the previous on all your numbers ... (just like you do with the . button)

Answer 2

As Noctis said you need to add to the previous in all your click events. Like :

private void some_button_Click(object sender, EventArgs e)
{
    txtDisplay.Text += ((Button)sender).Text;
}

Answer 3

the answer is simple

txtDisplay.Text += Button.Text;

Improve your code

public class Form1:Form
{
    public enum CalcStatus
    {
        None,
        Plus,
        Minus,
        Divide,
        Multiply
    };

    CalcStatus status = CalcStatus.None;
    bool bHasNewFlag = false;
    bool bHasEquals = false;
    Decimal dMemory1 = 0M;
    Decimal dMemory2 = 0M;

    private void CalcButton_Click(object sender, EventArgs e) // This event will be handled by Plus,Minus,Devide and Multiply
    {
        Decimal.TryParse(txtDisplay.Text,out dMemory1);
        switch(((button)sender).Text)
        {
            case "+":
                status = CalcStatus.Plus;
                break;
            case "-":
                status = CalcStatus.Minus;
                break;
            case "/":
                status = CalcStatus.Divide;
                break;
            case "*":
                status = CalcStatus.Multiply;
                break;
        }
        bHasNewFlag = true;
        bHasEquals =false;
        dMemroy2 = 0M;
    }
    private void NumButton_Click(object sender, EventArgs e) // This event will be handled by numbers (0-9)
    {
        int iNumber = 0;
        int.TryParse(((button)sender).Text, out iNumber);
        if (bHasNewFlag)
            txtDisplay.Text = string.empty;
        txtDisplay.Text += iNumber.ToString();
        bHasEquals =false;
        dMemroy2 = 0M;
    }
    private void EqualsTo_Click(object sender, EventArgs e) // This event will be handled by Equals To (=)
    {
        Decimal dVal = 0M;

        if (bHasEquals == false)
            Decimal.TryParse(txtDisplay.Text, out dMemory1);

        switch(status)
        {
            case "+":
                dVal = dMemory1 + dMemory2;
                break;
            case "-":
                status = CalcStatus.Minus;
                dVal = dMemory1 - dMemory2;
                break;
            case "/":
                dVal = dMemory1 / dMemory2;
                break;
            case "*":
                dVal = dMemory1 * dMemory2;
                break;
        }
        txtDisplay.Text = dVal;
        bHasEquals =true;           
    }
}

Do not take boolean flag for each button. because, you can do one thing at one time.

Updates: My suggestion is when you have status like Plus, Minus, Divide, etc. then you can do any one thing at a time. for example here you have to manage 4 variables on each button click instead of one. so use Enumaration when you have single status value.

 public enum CalcStatus
    {
        None,
        Plus,
        Minus,
        Divide,
        Multiply
    };
    CalcStatus status = CalcStatus.None;