小编hop*_*all的帖子

如何根据另一个字段的值有条件地验证一个字段？这是我尝试过的，但似乎不起作用

this.PDform = _formbuilder.group({
    [...]
    'intlNumber': ['',this.nationality == 'Abroad' ? Validators.compose([Validators.pattern(this.phoneNumberExp), Validators.maxLength(14), Validators.minLength(11), Validators.required]) : Validators ]
    [...]
})

我正在尝试使用以下代码将位图转换为 8bpp 灰度

private Bitmap ConvertPixelformat(ref Bitmap Bmp)
{
       Bitmap myBitmap = new Bitmap(Bmp);
        // Clone a portion of the Bitmap object.
        Rectangle cloneRect = new Rectangle(0, 0, Bmp.Width, Bmp.Height);
        PixelFormat format = PixelFormat.Format8bppIndexed;
        Bitmap cloneBitmap = myBitmap.Clone(cloneRect, format);
        var pal = cloneBitmap.Palette;

        for (i = 0; i < cloneBitmap.Palette.Entries.Length; ++i)
        {
            var entry = cloneBitmap.Palette.Entries[i];
            var gray = (int)(0.30 * entry.R + 0.59 * entry.G + 0.11 * entry.B);
            pal.Entries[i] = Color.FromArgb(gray, gray, gray);
        }
        cloneBitmap.Palette = pal;
        cloneBitmap.SetResolution(500.0F, …