Javascript/C# 手作りカレンダー

一般的にカレンダーを自作する必要性はないと思うけど、作る必要がでてきたのでとりあえずメモ。

<!doctype html>
<html lang="ja">
<head>
<meta charset="utf-8" />
</head>
<body>
<script>

let year = '2020';
let month = '1';

let html = '<table>';

html += '<tr>';
let week = ['日', '月', '火', '水', '木', '金', '土'];
for (let col = 0; col < week.length; col++) {
    html += '<td>' + week[col] + '</td>';
}
html += '</tr>';

let startWeekDay = new Date(year, month - 1, 1).getDay();
let endDay = new Date(year, month,  0).getDate();
let counter = 1;

// startWeekDay: 日0, 月1, 火2, 水3, 木4, 金5, 土6
// endDay: 最終日
// counter: 書込日付

// 縦6(0～5), 横7(0～6)のループ

for (let row = 0; row < 6; row++) {

    html += '<tr>';
    for (let col = 0; col < 7; col++) {

        if ((row == 0 && col < startWeekDay) || (counter > endDay)) {

            // 第1週と最終週の判定
            // 第1週: colが増えていき、startWeekDay以上の場合は日付が書き込まれる
            // 最終週: counterが増えていき、endDay以上になると空白

            html += '<td></td>';
        } else {
            html += '<td>' + counter + '</td>';
            counter++;
        }
    }
    html += '</tr>';
}
html += '</table>';

document.body.innerHTML = html;

</script>
</body>
</html>

<!doctype html>

<head>

</head>

<body>

let year = '2020';

let month = '1';

let html = '<table>';

html += '<tr>';

let week = ['日', '月', '火', '水', '木', '金', '土'];

for (let col = 0; col < week.length; col++) {

html += '<td>' + week[col] + '</td>';

}

html += '</tr>';

let startWeekDay = new Date(year, month - 1, 1).getDay();

let endDay = new Date(year, month, 0).getDate();

let counter = 1;

// startWeekDay: 日0, 月1, 火2, 水3, 木4, 金5, 土6

// endDay: 最終日

// counter: 書込日付

// 縦6(0～5), 横7(0～6)のループ

for (let row = 0; row < 6; row++) {

html += '<tr>';

for (let col = 0; col < 7; col++) {

if ((row == 0 && col < startWeekDay) || (counter > endDay)) {

// 第1週と最終週の判定

// 第1週: colが増えていき、startWeekDay以上の場合は日付が書き込まれる

// 最終週: counterが増えていき、endDay以上になると空白

html += '<td></td>';

} else {

html += '<td>' + counter + '</td>';

counter++;

}

html += '</tr>';

}

html += '</table>';

document.body.innerHTML = html;

</script>

</body>

</html>

C#(DataGridView)版

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace CreateCalendar
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            dataGridView1.AllowUserToAddRows = false;
            dataGridView1.DefaultCellStyle.WrapMode = DataGridViewTriState.True;

            List<DataGridViewTextBoxColumn> columns = new List<DataGridViewTextBoxColumn>();

            foreach(var s in new string[] { "日", "月", "火", "水", "木", "金", "土" })
            {
                columns.Add(new DataGridViewTextBoxColumn()
                {
                    HeaderText = s,
                    Width = 120,
                    SortMode = DataGridViewColumnSortMode.NotSortable
                });
            }

            dataGridView1.Columns.AddRange(columns.ToArray());

            int y = 2019;
            int m = 12;

            int startWeekDay = (int)new DateTime(y, m, 1).DayOfWeek; // 日=0, 月=1, 火=2, 水=3, 木=4, 金=5, 土=6
            int endDay = new DateTime(y, m, 1).AddMonths(1).AddDays(-1).Day;
            int counter = 1;

            for (int r = 0; r < 12; r++)
            {
                dataGridView1.Rows.Add();

                if (r % 2 == 0)
                {
                    dataGridView1.Rows[r].Height = 18;
                }
                else
                {
                    dataGridView1.Rows[r].Height = 80;
                }
            }

            for (int r = 0; r < 12; r = r + 2)
            {
                for (int c = 0; c < 7; c++)
                {
                    if ((r == 0 && c < startWeekDay) || counter > endDay)
                    {
                        dataGridView1.Rows[r].Cells[c].Value = "";
                    }
                    else
                    {
                        dataGridView1.Rows[r].Cells[c].Value = counter.ToString();
                        dataGridView1.Rows[r + 1].Cells[c].Value = "";

                        counter++;
                    }
                }
            }
        }
    }
}

using System;

using System.Collections.Generic;

using System.Windows.Forms;

namespace CreateCalendar

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

dataGridView1.AllowUserToAddRows = false;

dataGridView1.DefaultCellStyle.WrapMode = DataGridViewTriState.True;

List<DataGridViewTextBoxColumn> columns = new List<DataGridViewTextBoxColumn>();

foreach(var s in new string[] { "日", "月", "火", "水", "木", "金", "土" })

{

columns.Add(new DataGridViewTextBoxColumn()

{

HeaderText = s,

Width = 120,

SortMode = DataGridViewColumnSortMode.NotSortable

});

}

dataGridView1.Columns.AddRange(columns.ToArray());

int y = 2019;

int m = 12;

int startWeekDay = (int)new DateTime(y, m, 1).DayOfWeek; // 日=0, 月=1, 火=2, 水=3, 木=4, 金=5, 土=6

int endDay = new DateTime(y, m, 1).AddMonths(1).AddDays(-1).Day;

int counter = 1;

for (int r = 0; r < 12; r++)

{

dataGridView1.Rows.Add();

if (r % 2 == 0)

{

dataGridView1.Rows[r].Height = 18;

}

else

{

dataGridView1.Rows[r].Height = 80;

}

for (int r = 0; r < 12; r = r + 2)

{

for (int c = 0; c < 7; c++)

{

if ((r == 0 && c < startWeekDay) || counter > endDay)

{

dataGridView1.Rows[r].Cells[c].Value = "";

}

else

{

dataGridView1.Rows[r].Cells[c].Value = counter.ToString();

dataGridView1.Rows[r + 1].Cells[c].Value = "";

counter++;

}