您需要将 IWebHostEnvironment 注入到类中才能访问属性值 ApplicationBasePath：阅读有关依赖关系注入的信息。成功注入依赖项后，wwwroot 路径应该可供您使用。例如：
private readonly IWebHostEnvironment _appEnvironment;
public ProductsController(IWebHostEnvironment appEnvironment)
{
_appEnvironment = appEnvironment;
}用法：
[HttpGet]
public IEnumerable<string> Get()
{
FolderScanner scanner = new FolderScanner(_appEnvironment.WebRootPath);
return scanner.scan();
}编辑：在 ASP.NET 的更高版本中，IHostingEnvironment 已被替换为 IWebHostEnvironment。
O
转自 Oluwafemi
4 年前
4,446
不要使用 CSS 方式设置 canvas 的宽高，应使用属性来设置其尺寸。
直接设置属性：
<canvas id="canvas" width="400" height="300"></canvas>因属性值是以 px 为单位的，如果项目全程使用 rem 等其它尺寸单位，可通过 JS 来设置
var canvas = document.getElementById('canvas');
coatingW = $('#coating_frame').width();
coatingH = $('#coating_frame').height();
canvas.width = coatingW;
canvas.height = coatingH;
xoyozo
4 年前
2,164
项目 - 属性 - 生成 - 输出 - 文档文件，勾选“生成包含 API 文档的文件。”，“XML 文档文件路径”可留空。
在配置方法 AddSwaggerGen 中添加以下两行
var xmlFilename = $"{System.Reflection.Assembly.GetExecutingAssembly().GetName().Name}.xml"; options.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, xmlFilename));
xoyozo
4 年前
3,672
public static class EntityFrameworkCoreExtension
{
private static DbCommand CreateCommand(DatabaseFacade facade, string sql, out DbConnection connection, params object[] parameters)
{
var conn = facade.GetDbConnection();
connection = conn;
conn.Open();
var cmd = conn.CreateCommand();
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
return cmd;
}
public static DataTable SqlQuery(this DatabaseFacade facade, string sql, params object[] parameters)
{
var command = CreateCommand(facade, sql, out DbConnection conn, parameters);
var reader = command.ExecuteReader();
var dt = new DataTable();
dt.Load(reader);
reader.Close();
conn.Close();
return dt;
}
public static List<T> SqlQuery<T>(this DatabaseFacade facade, string sql, params object[] parameters) where T : class, new()
{
var dt = SqlQuery(facade, sql, parameters);
return dt.ToList<T>();
}
public static List<T> ToList<T>(this DataTable dt) where T : class, new()
{
var propertyInfos = typeof(T).GetProperties();
var list = new List<T>();
foreach (DataRow row in dt.Rows)
{
var t = new T();
foreach (PropertyInfo p in propertyInfos)
{
if (dt.Columns.IndexOf(p.Name) != -1 && row[p.Name] != DBNull.Value)
{
p.SetValue(t, row[p.Name], null);
}
}
list.Add(t);
}
return list;
}
}调用示例：
var data = db.Database.SqlQuery<List<string>>("SELECT 'title' FROM `table` WHERE `id` = {0};", id);我
转自 我的个去
4 年前
2,559
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
namespace xxx.xxx.xxx.Controllers
{
public class DiscuzTinyintViewerController : Controller
{
public IActionResult Index()
{
using var context = new Data.xxx.xxxContext();
var conn = context.Database.GetDbConnection();
conn.Open();
using var cmd = conn.CreateCommand();
cmd.CommandText = "SELECT `TABLE_NAME` FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE();";
Dictionary<string, List<FieldType>?> tables = new();
using var r = cmd.ExecuteReader();
while (r.Read())
{
tables.Add((string)r["TABLE_NAME"], null);
}
conn.Close();
foreach (var table in tables)
{
var conn2 = context.Database.GetDbConnection();
conn2.Open();
using var cmd2 = conn2.CreateCommand();
cmd2.CommandText = "DESCRIBE " + table.Key;
using var r2 = cmd2.ExecuteReader();
List<FieldType> fields = new();
while (r2.Read())
{
if (((string)r2[1]).Contains("tinyint(1)"))
{
fields.Add(new()
{
Field = (string)r2[0],
Type = (string)r2[1],
Null = (string)r2[2],
});
}
}
conn2.Close();
tables[table.Key] = fields;
}
foreach (var table in tables)
{
foreach (var f in table.Value)
{
var conn3 = context.Database.GetDbConnection();
conn3.Open();
using var cmd3 = conn3.CreateCommand();
cmd3.CommandText = $"SELECT {f.Field} as F, COUNT({f.Field}) as C FROM {table.Key} GROUP BY {f.Field}";
using var r3 = cmd3.ExecuteReader();
List<FieldType.ValueCount> vs = new();
while (r3.Read())
{
vs.Add(new() { Value = Convert.ToString(r3["F"]), Count = Convert.ToInt32(r3["C"]) });
}
conn3.Close();
f.groupedValuesCount = vs;
}
}
return Json(tables.Where(c => c.Value != null && c.Value.Count > 0));
}
private class FieldType
{
public string Field { get; set; }
public string Type { get; set; }
public string Null { get; set; }
public List<ValueCount> groupedValuesCount { get; set; }
public class ValueCount
{
public string Value { get; set; }
public int Count { get; set; }
}
public string RecommendedType
{
get
{
if (groupedValuesCount == null || groupedValuesCount.Count < 2)
{
return "无建议";
}
else if (groupedValuesCount.Count == 2 && groupedValuesCount.Any(c => c.Value == "0") && groupedValuesCount.Any(c => c.Value == "1"))
{
return "bool" + (Null == "YES" ? "?" : "");
}
else
{
return "sbyte" + (Null == "YES" ? "?" : "");
}
}
}
}
}
}[{
"key": "pre_forum_post",
"value": [{
"field": "first",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1395501
}, {
"value": "1",
"count": 179216
}],
"recommendedType": "bool"
}, {
"field": "invisible",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "-5",
"count": 9457
}, {
"value": "-3",
"count": 1412
}, {
"value": "-2",
"count": 1122
}, {
"value": "-1",
"count": 402415
}, {
"value": "0",
"count": 1160308
}, {
"value": "1",
"count": 3
}],
"recommendedType": "sbyte"
}, {
"field": "anonymous",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1574690
}, {
"value": "1",
"count": 27
}],
"recommendedType": "bool"
}, {
"field": "usesig",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 162487
}, {
"value": "1",
"count": 1412230
}],
"recommendedType": "bool"
}, {
"field": "htmlon",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1574622
}, {
"value": "1",
"count": 95
}],
"recommendedType": "bool"
}, {
"field": "bbcodeoff",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "-1",
"count": 935448
}, {
"value": "0",
"count": 639229
}, {
"value": "1",
"count": 40
}],
"recommendedType": "sbyte"
}, {
"field": "smileyoff",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "-1",
"count": 1359482
}, {
"value": "0",
"count": 215186
}, {
"value": "1",
"count": 49
}],
"recommendedType": "sbyte"
}, {
"field": "parseurloff",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1572844
}, {
"value": "1",
"count": 1873
}],
"recommendedType": "bool"
}, {
"field": "attachment",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1535635
}, {
"value": "1",
"count": 2485
}, {
"value": "2",
"count": 36597
}],
"recommendedType": "sbyte"
}, {
"field": "comment",
"type": "tinyint(1)",
"null": "NO",
"groupedValuesCount": [{
"value": "0",
"count": 1569146
}, {
"value": "1",
"count": 5571
}],
"recommendedType": "bool"
}]
}]
xoyozo
4 年前
2,430
Serialization and deserialization of 'System.DateOnly' / 'System.TimeOnly' instances are not support
System.NotSupportedException: Serialization and deserialization of 'System.DateOnly' instances are not supported.
The unsupported member type is located on type 'System.Nullable`1[System.DateOnly]'.
解决方法：
https://www.nuget.org/packages/DateOnlyTimeOnly.AspNet/
builder.Services
.AddControllers(options => options.UseDateOnlyTimeOnlyStringConverters())
.AddJsonOptions(options => options.UseDateOnlyTimeOnlyStringConverters());M
转自 Maksym Koshovyi
4 年前
6,608
POST
axios.post('AjaxCases', {
following: true,
success: null,
page: 1,
}).then(function (response) {
console.log(response.data)
}).catch(function (error) {
console.log(error.response.data);
});[HttpPost]
public IActionResult AjaxCases([FromBody] AjaxCasesRequestModel req)
{
bool? following = req.following;
bool? success = req.success;
int page = req.page;
}GET
axios.get('AjaxCase', {
params: {
int: 123,
}
}).then(function (response) {
console.log(response.data)
}).catch(function (error) {
console.log(error.response.data);
});[HttpGet]
public IActionResult AjaxCases([FromQuery] int id)
{
}DELETE
格式与 GET 类似
* 若服务端获取参数值为 null，可能的情况如下：
请检查相关枚举类型是否已设置 [JsonConverter] 属性，参：C# 枚举（enum）用法笔记，且传入的值不能为空字符串，可以传入 null 值，并将服务端 enum 类型改为可空。可以以 string 方式接收参数后再进行转换。
模型中属性名称不能重复（大小写不同也不行）。
布尔型属性值必须传递布尔型值，即在 JS 中，字符串 "true" 应 JSON.parse("true") 为 true 后再回传给服务端，vue 绑定方式参此文。
xoyozo
4 年前
3,761
iPhone 或安卓上传的照片，可能因横向或纵向拍摄，导致上传后照片显示成 90 度、180 度、270 度角旋转，使用 C# 处理该照片时同样会遇到相同的问题。
解决的方案：
客户端使用 base64 显示图片，可按正常方向显示，且不通过服务端即时显示。关键代码：
$('#file_input').change(function (e) {
if (e.target.files.length == 0) { return; }
// file 转换为 base64
var reader = new FileReader();
reader.readAsDataURL(e.target.files[0]);
reader.onload = function (event) {
$('#myImg').attr('src', event.target.result).css({ width: 'auto', height: 'auto' });
}
});
$('#myImg').on('load', function () {
console.log('图片加载完成')
});但 base64 字符串传递到服务端受请求大小限制（一般比直接 POST 文件要小）。所以显示图片的同时应即时使用 POST 方式上传图片（如 jquery.fileupload.js）。
当然如果是在微信中打开网页，使用 JS-SDK 的 wx.chooseImage() 返回的 localId 也可以在 <img /> 中正常显示，然后使用 wx.uploadImage() 上传到微信服务器并获取 serverId，在通过获取临时素材接口取回图片文件。
服务端如果需要处理该图片（缩放、裁切、旋转等），需要先读取照片的拍摄角度，旋正后，再进行处理，相关 C# 代码：
/// <summary>
/// 调整照片的原始拍摄旋转角度
/// </summary>
/// <param name="img"></param>
/// <returns></returns>
private Image ImageRotateFlip(Image img)
{
foreach (var prop in img.PropertyItems)
{
if (prop.Id == 0x112)
{
switch (prop.Value[0])
{
case 6: img.RotateFlip(RotateFlipType.Rotate90FlipNone); break;
case 3: img.RotateFlip(RotateFlipType.Rotate180FlipNone); break;
case 8: img.RotateFlip(RotateFlipType.Rotate270FlipNone); break;
}
prop.Value[0] = 1;
}
}
return img;
}
xoyozo
4 年前
4,110
当 ASP.NET 发布一个新的小版本更新时（以 .NET 5.0.10 为例），生产环境服务器端可以直接下载安装 .NET 5.0.10 来自动替换 .NET 5.0.9。
倘若这时直接使用 VS 将 nuget 中版本为 5.0.9 的组件更新到 5.0.10 发布到服务器上的话，可能会发生错误：
HTTP Error 500.30 - ASP.NET Core app failed to start
这里我们可以在 nuget 回滚相关组件的版本至 5.0.9，等 VS 发现新的版本更新时，更新 VS 开发工具后，再更新 nuget 组件并进行发布即可。
着急的小伙伴可以直接前往 Microsoft .NET 网站下载安装包含 Runtime 5.0.10 的 SDK：
该情况同样发生在 ASP.NET Core 3.1 等大版本上。
若仍未生效，请重启服务器。
----------------
后注：安装完成后重启服务器可避免以上烦恼！
xoyozo
4 年前
2,574
private static List<string> GetTableNames(DbContext context)
{
context.Database.OpenConnection();
var connection = context.Database.GetDbConnection();
using var command = connection.CreateCommand();
command.CommandText = @"SELECT `TABLE_NAME`
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = DATABASE();";
var tableNames = new List<string>();
using var reader = command.ExecuteReader();
while (reader.Read())
{
tableNames.Add((string)reader["TABLE_NAME"]);
}
return tableNames;
}l
转自 lauxjpn
4 年前
2,851