c# - 使用 DateTime.ParseExact C# 未将字符串识别为有效的 DateTime

Question

以为我解决了这个问题，但我仍然遇到问题。尝试运行此代码以在提示中从用户输入中解析日期和时间，但每次我尝试 DateTime.ParseExact 时都会收到错误格式无效。样本日期:太平洋夏令时间 2015 年 7 月 24 日晚上 9:08:19太平洋夏令时间 2015 年 7 月 26 日下午 2:13:54

        string afterpromptvalue = Prompt.ShowDialog("Enter earliest Date and Time", "Unshipped Orders");
        string beforepromptvalue = Prompt.ShowDialog("Enter latest Date and Time", "Unshipped Orders");

        string format = "MMM d, yyyy h:m:s tt PDT";
        CultureInfo provider = CultureInfo.InvariantCulture;

        DateTime createdAfter = DateTime.ParseExact(afterpromptvalue, format, provider);
        DateTime createdBefore = DateTime.ParseExact(beforepromptvalue, format, provider);`enter code here`

提示框代码如下:

public static class Prompt
{
    public static string ShowDialog(string text, string caption)
    {
        Form prompt = new Form();
        prompt.Width = 500;
        prompt.Height = 150;
        prompt.FormBorderStyle = FormBorderStyle.FixedDialog;
        prompt.Text = caption;
        prompt.StartPosition = FormStartPosition.CenterScreen;
        Label textLabel = new Label() { Left = 50, Top=20, Text=text };
        TextBox textBox = new TextBox() { Left = 50, Top=50, Width=400 };
        Button confirmation = new Button() { Text = "Ok", Left=350, Width=100, Top=70, DialogResult = DialogResult.OK };
        confirmation.Click += (sender, e) => { prompt.Close(); };
        prompt.Controls.Add(textBox);
        prompt.Controls.Add(confirmation);
        prompt.Controls.Add(textLabel);
        prompt.AcceptButton = confirmation;

        return prompt.ShowDialog() == DialogResult.OK ? textBox.Text : "";
    }

Answer 1

考虑到你的两个字符串，你只需要使用 mm specifier而不是 m specifier因为你的个位数分钟有 leading zeros .

string format = "MMM d, yyyy h:mm:s tt PDT";

举个例子；

string s = "Jul 24, 2015 9:08:19 PM PDT";
DateTime dt;
if(DateTime.TryParseExact(s, "MMM d, yyyy h:mm:s tt PDT", CultureInfo.InvariantCulture,
                          DateTimeStyles.None, out dt))
{
    // 24.07.2015 21:08:19
}

和

string s = "Jul 26, 2015 2:13:54 PM PDT";
DateTime dt;
if(DateTime.TryParseExact(s, "MMM d, yyyy h:mm:s tt PDT", CultureInfo.InvariantCulture,
                          DateTimeStyles.None, out dt))
{
    // 26.07.2015 14:13:54
}