How to disable buttons when TextBox is empty?

Question

I want to disable button until there is text in TextBox. How can I do it? I'm beginner and I don't know anything so just a code that I should add is great. My code:
private void button1_Click(object sender, EventArgs e) {

        double wiek = double.Parse(textBox1.Text);
        double gotowka = double.Parse(textBox2.Text);

        if (wiek >= 15 && gotowka >= 30 || gotowka >= 130)
        {
            MessageBox.Show("Możesz wejść!");
        }
        else
        {
            MessageBox.Show("Nie możesz wejść!");
        }

        if (wiek >= 15 && gotowka >= 30)
        {
            double reszta = gotowka - 30;
            textBox3.Text = reszta.ToString();
        }

        if (wiek < 15 && gotowka >= 130)
        {
            double reszta2 = gotowka - 130;
            textBox3.Text = reszta2.ToString();

        }

        if (wiek < 15 && gotowka >= 30)
        {
            double reszta3 = gotowka;
            textBox3.Text = reszta3.ToString();
        }

        if (wiek >=15 && gotowka < 30)
        {
            double reszta4 = gotowka;
            textBox3.Text = reszta4.ToString();
        }
        if (wiek >= 15 && gotowka >= 130)
        {
            double reszta5 = gotowka - 30;
            textBox3.Text = reszta5.ToString();
        }
        if (wiek < 15 && gotowka >= 130)
        {
            double reszta6 = gotowka - 130;
            textBox3.Text = reszta6.ToString();
        }

Assuming you're talking about WinForms. This should get you started: learn.microsoft.com/en-us/dotnet/framework/winforms/… You basically need to write event handlers for a variety of events, check the values and then set the Enabled property for your textbook to true or false. — Jason Armstrong
– Jason Armstrong, Commented Nov 7, 2018 at 15:45
Possible duplicate of How to disable button if textbox is empty — Sinatr
– Sinatr, Commented Nov 7, 2018 at 15:45

IMm0rtal · Accepted Answer · 2022-12-09 18:48:38Z

1

Your code isn't relevant to what you asked, but anyway

If you want to check every case where your textbox is empty, you should check weather it's empty or not in two places:

In the loaded event of your form (Form1_Loaded).
In the TextChanged event of the textBox

As following :

if (textBox1.Text == "")
{
    button1.Enabled = false;
}
else 
{
    button1.Enabled = true;
}

If you're too beginner to understand what I wrote, tell me in a comment to walk you through it ♥

answered Dec 9, 2022 at 18:48

IMm0rtal

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Comments

Techcraft7 · Accepted Answer · 2018-11-07 16:30:20Z

0

Here's how I would do it! Step 1. add a TextChanged event by double clicking your textbox in the windows forms designer. Step 2. enter this code into the event, replace MyTextBox with the name of your text box, and MyButton with the name of your button!

if (MyTextBox.Text == "")
{
    //(if you would like to make the button disappear, do this)
    MyButton.Visible = false;
    //(if you would like to make the button gray out, do this)
    MyButton.Enabled = false;
}
else
{

    //(if you would like to make the button disappear, do this)
    MyButton.Visible = true;
    //(if you would like to make the button gray out, do this)
    MyButton.Enabled = true;

}

Hope this helps!

Techcraft7 :)

answered Nov 7, 2018 at 16:30

Techcraft7

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Comments

Crick3t · Accepted Answer · 2018-11-07 16:32:35Z

0

To do this you would need to add an event handler for the text box. Either on Leave or TextChanged. There you could enable and disable the button.

On the other hand, can it be that you want this just because the parse throws an exception if the text box is empty? Even if it is not empty it can contain any text that could not be converted to a double.

A better solution could be to change the

double wiek = double.Parse(textBox1.Text);
double gotowka = double.Parse(textBox2.Text);

To

double wiek;
double gotowka;

bool isParsed = double.TryParse(textBox1.Text, out wiek);
if (!isParsed)
{
   //TODO: some error handling, telling the user it is not a number
   MessageBox.Show("Nie numer!");
   return;
}

isParsed = double.TryParse(textBox2.Text, out gotowka);
if (!isParsed)
{
   //TODO: some error handling, telling the user it is not a number
   MessageBox.Show("Nie numer!");
   return;
}

edited Nov 7, 2018 at 16:32

answered Nov 7, 2018 at 15:53

Crick3t

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5 Comments

Bałwan Over a year ago

That does the first part, but now I'm getting error with double gotowka .

Crick3t Over a year ago

you just need to do the same with the other number as well. "bool isParsed = double.TryParse(textBox2.Text, out gotowka); if (!isParsed)..."

Crick3t Over a year ago

I have added the check to the other variable too.

Bałwan Over a year ago

Agh I don't know why it's not working, but thanks for the help

Crick3t Over a year ago

I have added some "error handling". Could you please try the code above? Also, what do you mean by it is not working?

Edis_Ak · Accepted Answer · 2019-11-14 10:16:23Z

0

if (MyTextBox.Text == "")
{
    //(if you would like to make the button disappear, do this)
    MyButton.Visible = false;
    //(if you would like to make the button gray out, do this)
    MyButton.Enabled = false;
}
else
{

    //(if you would like to make the button disappear, do this)
    Button.Visible = true;
    //(if you would like to make the button gray out, do this)
    Button.Enabled = true;

}

answered Nov 14, 2019 at 10:16

Edis_Ak

1

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