Question

[基于回复的编辑版本]

我只希望同时填充文本框和datetimepicker才能启用button1。我可以为文本做，但不能为datetimepicker做。这是我的完整代码。仅供参考：我的datetimepicker最初被格式化为空，以便用户自己选择日期。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Inspection
  {
    public partial class Vdetails : Form
     {
    public Vdetails()

    {
        InitializeComponent();
        Vnew.Enabled = false; 
    }

    //Allow user input date
    private void DTafes_ValueChanged(object sender, EventArgs e)
    {
        DTafes.CustomFormat = @"";
    }
    private void DTfa_ValueChanged_1(object sender, EventArgs e)
    {
        DTfa.CustomFormat = @"";
    }
    private void DTfe_ValueChanged(object sender, EventArgs e)
    {
        DTfe.CustomFormat = @"";
    }

    //Condition to allow button to go next
    private void ActivateButton()
    {
        Button1.Enabled = (Vehicle.Text != "" && Distance.Text != "");
    }

    private void Vehicle_TextChanged(object sender, EventArgs e)
    {
        ActivateButton();
    }

    private void Distance_TextChanged(object sender, EventArgs e)
    {
        ActivateButton();
    }
}

我如何添加代码以及如何添加代码以允许填充datetimepicker。希望有人能帮助我。

Answer 1

DateTimePicker总是有一个值，但是您可以收听ValueChanged事件

private bool dateChanged;
protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);
    dateChanged = false;
    button1.Enabled = false;
}

private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
{
    dateChanged = true;
    SetEnabledness();
}

private void SetEnabledness()
{
    button1.Enabled = !string.IsNullOrWhiteSpace(textBox1.Text) && dateChanged;
}

private void textBox1_TextChanged(object sender, EventArgs e)
{
    SetEnabledness();
}

如果您有多个DateTimePicker，则可以使用HashSet代替bool（只需确保将所有ValueChangedEvents连接到dp_ValueChanged例如

    private HashSet<DateTimePicker> dateChanged = new HashSet<DateTimePicker>();
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        dateChanged.Clear();
        button1.Enabled = false;

        dateTimePicker1.Format = DateTimePickerFormat.Custom;
        dateTimePicker2.Format = DateTimePickerFormat.Custom;
        dateTimePicker3.Format = DateTimePickerFormat.Custom;
        dateTimePicker1.CustomFormat = @" ";
        dateTimePicker2.CustomFormat = @" ";
        dateTimePicker3.CustomFormat = @" ";
    }

    private void dp_ValueChanged(object sender, EventArgs e)
    {
        var dp = (DateTimePicker) sender;
        dp.Format = DateTimePickerFormat.Short;
        dateChanged.Add(dp);
        SetEnabledness();
    }

    private void SetEnabledness()
    {
        button1.Enabled = !string.IsNullOrWhiteSpace(textBox1.Text) && dateChanged.Count == 3;
    }

    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        SetEnabledness();
    }

Answer 2

dateTimePicker没有textchanged事件。 dateTimePicker内永远不会有空字符串。（也许可以通过代码来设置它，但是不能通过用户输入来设置它）。当用户更改日期时，可以使用dateTimePicker的valueChanged-event进行操作。

由于文本永远不会为空，因此您不必在ActiveButton函数中对其进行检查。

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    private void ActiveateButton()
    {
        this.button1.Enabled = textBox1.Text != string.Empty;
    }


    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        ActiveateButton();
    }
    private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
    {
        ActiveateButton();
    }
}

仅当文本框和日期时间选择器已填写时才能启用按钮

2 个答案: