将字符串值添加到数组

Question

I have this piece of code and this may seem like a very stupid question but it is they way I was taught to do it and it is not working correctly for me.

I wanted it to be that when I entered text into the txtEnterWord text box it would be added to the array words and displayed in the list box lstWords .

But every time I go to add a second word it clears the previous word and replaces it with the new one. Anyone know how to fix this? :)

 private void btnEnter_Click(object sender, EventArgs e)
        {
            //string[] words = new string[6];
            //words[6] = txtEnterWord.Text;

            //for (int i = 0; i < words.Length; i++)
            //{
            //    lstWords.Items.Add(words[i]);
            //}

            lstWords.Items.Clear();
            string[] words = new string[6];

            //words[0] = txtEnterWord.Text;
            //words[1] = txtEnterWord.Text;
            //words[2] = txtEnterWord.Text;
            //words[3] = txtEnterWord.Text;
            //words[4] = txtEnterWord.Text;
            //words[5] = txtEnterWord.Text;

            for (int i = 0; i < words.Length;i++)
            {
                //words[i] = txtEnterWord.Text;
                lstWords.Items.Add(txtEnterWord.Text);
                txtEnterWord.Clear();
                //lstWords.ToString() = lstWords.ToString() + words[i].ToString();
            }

Answer 1

You're clearing the array every time you enter btnEnter_Click method, you should declare int as a variable for your page, like a "global" variable and in the btnEnter_Click method you should only add the new value. Sorry for bad english.

Answer 2

It should just be the below code. No need for a for loop and you shouldn't be clearing lstWords.Items because that is why your data is disappearing. Just add the textbox Text to your list and then clear the textbox. You also don't need the string[] words because it is doing nothing as a local variable. If you really wanted to add it to a string[] then it would need to be a member of the class this method is in. I think just doing lstWords.Items.Add should be good though if that's where you need the text to be saved.

private void btnEnter_Click(object sender, EventArgs e)
{
    lstWords.Items.Add(txtEnterWord.Text);
    txtEnterWord.Clear();
}

Answer 3

private void button1_Click(object sender, EventArgs e)
{
    string words;
    words = textBox1.Text;
    listBox1.Items.Add(words);
    textBox1.Clear();
}

Answer 4

If you are trying to add continuously a new item to the list, you should not clear the lstWords.Items if you want to keep them visually. I recommend you to create a List<string> myWordsToDisplay = new List<string>() globaly and add an item to the list at the time you click on the button add.

You should have your logic of clearing the list box on the event "OnPaint" or "OnLoad" of your application that depends clearly on which kind of project you have, something like this

OnPaint(EventArgs e)
{
    lstWords.Items.Clear();
    lstWords.Items.AddRange(myWordsToDisplay); //if the AddRange method is not present is the same thing as this myWordsToDisplay.ForEach(x => lstWords.Items.Add(x)
}

got the idea?

Answer 5

If you want every item to add to the listbox you should NOT call the method beneath. This function will clear all the items you have currently in the list thus making it appear empty.

lstWords.Items.Clear();

Instead you should just add the text from the textbox (txtEnterWord) to the listbox items.

 lstWords.Items.Add(txtEnterWord.Text);

If you want the value to also be stored somewhere else you should make this variable outside the button click function. If you want to be able to easily add items to an array, consider using a list. More information can be found here: https://msdn.microsoft.com/en-us/library/6sh2ey19(v=vs.110).aspx

Your complete code should look something like this.

private List<string> words = new List<string>();
private void btnEnter_Click(object sender, EventArgs e)
{
     words.Add(txtEnterWord.Text);
     lstWords.Items.Add(txtEnterWord.Text);
     txtEnterWord.Clear();
}