如果在 forms 中未选择所有选项，如何停止代码执行

Question

I am creating a simple form that prompts the user with 2 radio box selections. 1 of the selections is the color and the other is the form size. I need to create a code that forces the user to choose both a color and size option or no changes will happen to the form. How would I create this? Example to help out.

Sally checks blue but doesn't pick a form size and clicks the "Save form settings" button. It should not save anything to the form at all unless she chooses a form size. And vise versa, if she chooses only a size but no color no changes should be executed unless all options are picked.

private void button1_Click(object sender, EventArgs e)
        {
            // changes color of form
            if (radioButton1.Checked)
            {
                this.BackColor = Color.Blue;
            }
            else if (radioButton2.Checked)
            {
                this.BackColor = Color.Red;
            }
            else
            {
                this.BackColor = Color.Yellow;
            }
            // changes size of form
            if (radioButton3.Checked)
            {
                this.Size = new System.Drawing.Size(500, 500);
            }
            else if (radioButton4.Checked)
            {
                this.Size = new System.Drawing.Size(750, 750);
            }
            // executing changes for small and large blue form
            if (radioButton1.Checked && radioButton3.Checked)
            {
                textBox1.Text = "A Small, Blue form";
            }
            else if (radioButton1.Checked && radioButton4.Checked)
            {
                textBox1.Text = "A Large, Blue form";
            }
            // executing changes for small and large red form
            if (radioButton2.Checked && radioButton3.Checked)
            {
                textBox1.Text = "A Small, Red form";
            }
            else if (radioButton2.Checked && radioButton4.Checked)
            {
                textBox1.Text = "A Large, Red form";
            }
            // executing changes for small and large yellow form (i accidently named the yellow radio button "yellow" and it wouldn't let me change it so thats why it looks funny)
            if (Yellow.Checked && radioButton3.Checked)
            {
                textBox1.Text = "A Small, Yellow form";
            }
            else if (Yellow.Checked && radioButton4.Checked)
            {
                textBox1.Text = "A Large, Yellow form";
            }
            // code so both selections have to be made
            if (radioButton1.Checked == false)
            {

            }
            else if (radioButton2.Checked == false)
            {

            }
            else
            {

            }
            if (radioButton3.Checked == false)
            {

            }
            else
            {

            }
        }

If you have any tips on how to clean this up and make it better also please let me know.

Answer 1

One way to do this would be to capture the color and size separately into variables based on the values selected in the radio buttons, and then if no value is selected for a radio button group, use a default value that we can verify later.

For example, if we were going to set the color, we might do something like:

var color = Color.Empty;
if (rdoRed.Checked) color = Color.Red;
else if(rdoBlue.Checked) color = Color.Blue;
else if (rdoYellow.Checked) color = Color.Yellow;

By doing this, we know that if color == Color.Empty , then the user didn't select a color. We can apply the same logic with the Size property, and then we can use an if condition to verify that neither of the values are empty before changing the form size.

The ternary operator ( ?: ) can help shorten our code:

private void btnApplyChanges_Click(object sender, EventArgs e)
{
    // Set this to the value they chose, or 'Empty' if no choice was made
    var color = rdoBlue.Checked ? Color.Blue 
        : rdoYellow.Checked ? Color.Yellow 
        : rdoRed.Checked ? Color.Red 
        : Color.Empty;

    // Set this to the value they chose, or 'Empty' if no choice was made
    var size = rdoSmall.Checked ? new Size(500, 500) 
        : rdoLarge.Checked ? new Size(750, 750) 
        : Size.Empty;

    // If neither value is empty, then change our form properties
    if (color != Color.Empty && size != Size.Empty)
    {
        // If we get this far, we know size was selected. So we choose the word "Small"
        // if the height is 500, otherwise "Large" (there are better ways to do this)
        var sizeText = size.Height == 500 ? "small" : "large";
        txtStatus.Text = $"A {sizeText}, {color.Name} form";
        BackColor = color;
        Size = size;
    }
}

Answer 2

I'm not sure how you will handle all of these controls without using GroupBox . If you use GroupBox to group all releated RadioButton controls, you can loop over them using the groupbox.

Example:

foreach(var control in groupbox.Controls)
{
    if(control is RadioButton)
    {
        var radio = control as RadioButton; 

        var name = radio.Name;

        if(radio.Checked) { ... }
    }

}

You can do the same thing using the main Form as the container, but this would loop over all the form controls, which wouldn't be a good idea.

Secondly, you can define private methods that would handle some parts of the code, which would make things easier to handle like a method to set the size, another to set a color, another to get the message for a chosen size, and similarly you do the same for the color. In the end, you'll only pass a value to these methods, and then you process the results as you want.

here is an example:

private System.Drawing.Size GetSize(string radioButtonName)
{
    switch(radioButtonName)
    {
        case "radioButton3":
            return new System.Drawing.Size(500, 500);
        case "radioButton4":
            return new System.Drawing.Size(750, 750);
        default: // set a default size
            return Size.Empty;
    }   
}

private Color GetColor(string radioButtonName)
{
    switch(radioButtonName)
    {
        case "radioButton1":
            return Color.Blue;
        case "radioButton2":
            return Color.Red;
        case "Yellow":
            return Color.Yellow;            
        default: // set a default color
            return Color.Empty;
    }   
}

private string GetSizeTextMessage(int width)
{
    switch(width)
    {
        case 500:
            return "Small";
        case 750:
            return "Large";
        default: 
            return null;
    }   
}

Now, with this, you can add or adjust any settings you want to them. Then, in your main click event, you can do something like this:

string sizeRadioName; 
string colorRadioName;

// changes color of form
if (radioButton1.Checked)
{
    colorRadioName = radioButton1.Name;
}
else if (radioButton2.Checked)
{
    colorRadioName = radioButton2.Name;
}

// changes size of form
if (radioButton3.Checked)
{
    sizeRadioName = radioButton3.Name;
}
else if (radioButton4.Checked)
{
    sizeRadioName = radioButton4.Name
}

if(size != Size.Empty && color != Color.Empty) { 

    this.Size  = GetSize(sizeRadioName);
    this.BackColor = GetColor(colorRadioName);
    textBox1.Text = $"A {GetSizeTextMessage(this.Size.Width)} , {this.BackColor.Name} form";        
}   

this is for your current implementation, if you used a GroupBox it would changed to something like this:

Size size; 
Color color; 

foreach(var control in groupBoxExample.Controls)
{
    if(control.GetType() != typeof(RadioButton)) { continue; }

    var radio = control as RadioButton; 

    var name = radio.Checked ? radio.Name : null;

    if(name == null) { continue; }

    size  = GetSize(name);

    color = GetColor(name);
}

if(size != Size.Empty && color != Color.Empty) { 

    this.Size  = size;
    this.BackColor = color;
    textBox1.Text = $"A {GetSizeTextMessage(this.Size.Width)} , {this.BackColor.Name} form";        
}       

As you can see in this, we just put all the radios inside a group box, and I looped over them.

I hope this would help you out.