c# - 向 String.Join 添加新行？

Question

所以我一直在疯狂地尝试在我的 String.Join 打印输出中添加一个新行，但似乎这是不可能的，或者我做错了什么？我都尝试过使用 "/n/r" 和 Enivrorment.NewLine 以及创建一个类也创建一个新行

列表框我也想打印出来

ListBox1.Items.Add("Calories to lose 0.5kg per week: " +
    string.Join(Environment.NewLine + "Calories to lose 1kg per week:",
        bc.LoseOrGainWeightCalories(bc.MaintainWightCalories(), true)));

调用这个类:

public string[] LoseOrGainWeightCalories(double weight, bool lose) {
    string[] array = new string[2];
    double LoseGainWeight = this.weight;
    if(lose==true) {
        array[0] = Convert.ToString(LoseGainWeight - 500);
        array[1] = Convert.ToString(LoseGainWeight - 1000);
    } else {
        array[0] = Convert.ToString(LoseGainWeight + 500);
        array[1] = Convert.ToString(LoseGainWeight + 1000);
    }
    return array;
}

当前输出图片:

Answer 1

问题不在于 String.Join 方法:

$ csharp
csharp> string.Join(Environment.NewLine + "Calories to lose 1kg per week:",new double[] {13,21});
"13
Calories to lose 1kg per week:21"

因此，问题出在不呈现新行的 ListBox 上。您可以使用两种不同的解决方案来解决:

1. 添加多个项目，如图所示here

因此您可以将每一行添加为一个新项目。这种方法的问题是用户可以选择一行，除非您愿意编写解决方案来防止这种情况发生。

因此您可以执行:

string s = "Calories to lose 0.5kg per week: " +
string.Join(Environment.NewLine + "Calories to lose 1kg per week:",
    bc.LoseOrGainWeightCalories(bc.MaintainWightCalories(), true));
foreach (string si in Regex.Split(s,"\n"))
    ListBox1.Items.Add(si); 

1. 编写一个渲染器，用多行写入一个元素，如所演示的 here .

(复制重要部分)

ListBox1.DrawMode = DrawMode.OwnerDrawVariable;
private void listBox1_MeasureItem(object sender, MeasureItemEventArgs e) {
    int i = e.Index;
    float heightLine = 10.0f;
    string lines = listBox1.Items[i].ToString()Split(new string[] {Environment.NewLine},StringSplitOptions.None).Length;
    e.ItemHeight = (int) Math.Ceil(heightLine*itemi);
}
private void listBox1_DrawItem (object sender, DrawItemEventArgs e) {
   e.DrawBackground();
   e.Graphics.DrawString(listBox1.Items[e.Index].ToString(), e.Font, new SolidBrush(e.ForeColor), e.Bounds);
}
ListBox1.MeasureItem += listBox1_MeasureItem;
ListBox1.DrawItem += listBox1_DrawItem;