如何在表單中的二維數組中刪除 C# 中的項目行

Question

您好，我想知道如何使用按鈕從 C# 表單中的數組中刪除一行，就像您寫下要刪除的行#，然后按下按鈕將從列表中刪除該項目。 這個想法是使用“按鈕 2”刪除一行，該按鈕讀取寫在“文本框”中的數字。 以及如果該行不存在如何顯示警告消息。 我不能使用“list<>”或“grid thing”。 謝謝你們中的任何一個人可以借給我。 `公共部分類Form1：Form {

    int pos = 0;
    int counter = 0;
    string[,] sales = new String[50, 5];

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {

        string product;
        double price, subtotal, total;
        int qty;

        textBox1.BackColor = Color.White;
        if (textBox1.Text == "")
        {
            textBox1.BackColor = Color.Red;
            textBox1.Focus();
            MessageBox.Show("MISSING PRODUCT!!!");
            return;
        }
            textBox2.BackColor = Color.White;
            if (textBox2.Text == "")
        {
            textBox2.BackColor = Color.Red;
            textBox2.Focus();
            MessageBox.Show("MISSING PRODUCT!!!");
             return;
        }
            textBox3.BackColor = Color.White;
            if (textBox3.Text == "")
        {
            textBox3.BackColor = Color.Red;
            textBox3.Focus();
            MessageBox.Show("MISSING PRODUCT!!!");
             return;
        }


        product = textBox1.Text;
        price = double.Parse(textBox2.Text);
        qty = int.Parse(textBox3.Text);
        subtotal = price * qty;

        sales[pos, 0] = pos.ToString();
        sales[pos, 1] = product;
        sales[pos, 2] = price.ToString();
        sales[pos, 3] = qty.ToString();
        sales[pos, 4] = subtotal.ToString();

        pos++;

      
        textBox5.Text = "";
        total = 0;
        for (int i = 0; i < sales.GetLength(0); i++)
        {

            textBox5.Text += sales[i, 0] + "      " + sales[i, 1] + "      " + sales[i, 2] + "      " + sales[i, 3] + "      " + sales[i, 4] + "      " + "\r\n";
            //<>
            if (sales[i, 4] != null)
            {
                total += int.Parse(sales[i, 4]);
            }

        }
             textBox4.Text = total.ToString();
            
            textBox1.Text = "";
            textBox2.Text = "";
            textBox3.Text = "";
            textBox1.Focus();

    }

    private void button2_Click(object sender, EventArgs e)
    {
          
       // what to put here

    }
}

`

Answer 1

語境

我將在這里給你兩個答案，因為你不清楚是否需要使用數組而不是List<> 。 我也有點不確定你到底要什么，因為你沒有給出任何你希望輸出的例子，或者類似的東西，所以如果我完全錯過了標記，我深表歉意。 只要讓我知道，我會更改我的答案以更恰當地匹配您的要求:)

使用數組

private void button2_Click(object sender, EventArgs e)
{
    //Checks to see if the desired row to delete exists
    if(sales[pos][0] is null)
    {
        //Lets the user know the index is already empty
        MessageBox.Show("Index has no product listed.");
        return;
    }
    
    //Loops through each item at the pos index
    for(int i = 0; i < sales.GetLength(1); i++)
    {
        //remove
        sales[pos][i] = null;
    }

    /*******************************************************
    * I'm unsure if you would want to drop the index of all
    * of the arrays with a larger index number down one, so
    * this next bit of code will do this, but if you don't
    * want this functionality, just ignore this.
    ********************************************************/

    //Loops through every index from pos to the second to last index
    for(int i = pos; i < sales.GetLength(0) - 1; i++)
    {
        //Loops through every index of a product
        for(int j = 0; j < sales.GetLength(1); j++)
        {
            //Sets current row to the value in the next
            sales[i][j] = sales[i+1][j];
        }
    }
}

使用List<>

/*****************************************************
* I've changed the name of the variable to pascal case
* as this is Microsoft's documentation standard.
* This also shows how you would need to change the 
* declaration of the Sales object.
*****************************************************/
List<List<string>> Sales = new List<List<string>>();

private void button2_Click(object sender, EventArgs e)
{
    //Checks if the index is out of bounds of the list.
    if(pos > Sales.Count() - 1)
    {
        //Lets the user know the index out of bounds
        MessageBox.Show("Index is out of bounds.");
        return;
    }
    
    //Remove the product at the selected index
    Sales.RemoveAt(pos);
}

產品

我注意到您似乎正在嘗試列出要出售的產品。 我建議您創建一個Product類，其中包含產品所具有的所有信息。 一個快速的模擬可能看起來像這樣：

public class Product 
{
    /**********************************************************
    * If you are unfamiliar with how properties work, 
    * I recommend looking into them more, but quick, simplified
    * explanation is they are just variables you access from
    * other classes that have access to this one by
    * saying, in this case, Product.AttributeOne, and you
    * can even set it by writing Product.AttributeOne = "foo";
    **********************************************************/
    
    public string AttributeOne { get; set; }
    public string AttributeTwo { get; set; }
    public string AttributeThree { get; set; }
    public string AttributeFour { get; set; }
    public string AttributeFive { get; set; }
    
}

使用此類可以簡化您擁有的其他代碼，並使您的數組/列表成為一維的。 我強烈建議將產品作為對象，就像它可以用更少的代碼為您提供更多功能一樣。 我將向您展示button1_Click和button2_Click()的代碼在此更改后的樣子

public partial class Form1 : Form
{

    int pos = 0;
    int counter = 0;
    List<Product> Sales = new List<Product>();

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {

        string product;
        double price, subtotal, total;
        int qty;

        textBox1.BackColor = Color.White;

        if (textBox1.Text == "")
        {
            textBox1.BackColor = Color.Red;
            textBox1.Focus();
            MessageBox.Show("MISSING PRODUCT!!!");
            return;
        }

        textBox2.BackColor = Color.White;

        if (textBox2.Text == "")
        {
            textBox2.BackColor = Color.Red;
            textBox2.Focus();
            MessageBox.Show("MISSING PRODUCT!!!");
            return;
        }

        textBox3.BackColor = Color.White;

        if (textBox3.Text == "")
        {
            textBox3.BackColor = Color.Red;
            textBox3.Focus();
            MessageBox.Show("MISSING PRODUCT!!!");
            return;
        }


        product = textBox1.Text;
        price = double.Parse(textBox2.Text);
        qty = int.Parse(textBox3.Text);
        subtotal = price * qty;

        Sales.ElementAt(pos).AttributeOne = pos.ToString();
        Sales.ElementAt(pos).AttributeTwo = product;
        Sales.ElementAt(pos).AttributeThree = price.ToString();
        Sales.ElementAt(pos).AttributeFour = qty.ToString();
        Sales.ElementAt(pos).AttributeFive = subtotal.ToString();

        pos++;

  
        textBox5.Text = "";
        total = 0;

        for (int i = 0; i < Sales.Count; i++)
        {

            textBox5.Text += Sales.ElementAt(i).AttributeOne + "      " + Sales.ElementAt(i).AttributeTwo + "      " + Sales.ElementAt(i).AttributeThree + "      " + Sales.ElementAt(i).AttributeFour + "      " + Sales.ElementAt(i).AttributeFive + "      " + "\r\n";
            //<>
            if (Sales.ElementAt(i).AttributeFive != null)
            {
                total += int.Parse(sales[i, 4]);
            }

        }

        textBox4.Text = total.ToString();
            
        textBox1.Text = "";
        textBox2.Text = "";
        textBox3.Text = "";
        textBox1.Focus();

    }

    private void button2_Click(object sender, EventArgs e)
    {
        //Checks if the index is out of bounds of the list.
        if(pos > Sales.Count() - 1)
        {
            //Lets the user know the index out of bounds
            MessageBox.Show("Index is out of bounds.");
            return;
        }
        
        //Remove the product at the selected index
        Sales.RemoveAt(pos);
    }
}