如何在 c# 的日期时间选择器中添加秒数？

Question

I want that when you press a button, it adds 30 seconds to the date timer picker. but what happens to me is that they do not add up.

This is my code:

public partial class Form1 : Form
{
    double seg;

    public void Form1_Load(object sender, EventArgs e)
    {
        this.dateTimePicker1.Value = this.dateTimePicker1.Value.AddSeconds(seg);    
    }
    private void s30_Click(object sender, EventArgs e)
    {
        seg = 30;
    }
}

Answer 1

Update the control's value in the click event:

private void s30_Click(object sender, EventArgs e)
{
    seg = 30;
    this.dateTimePicker1.Value = this.dateTimePicker1.Value.AddSeconds(seg);
}

The Form_Load event only happens when the form is first loaded. (Note that this is specific to Windows Forms. In Web Forms you'll need to take this a step further and persist the value somewhere, because every post-back would load a new instance of the form and the value would start over.)

Of course, since seg never changes to anything but its hard-coded value, you don't really need it. Just increment the seconds by that hard-coded value:

private void s30_Click(object sender, EventArgs e)
{
    this.dateTimePicker1.Value = this.dateTimePicker1.Value.AddSeconds(30);
}

Then you can remove the seg variable from your code entirely.