前言
上一章节我们引入BootstrapBlazor UI组件完成了EasySQLite后台界面的基本架子的搭建，本章节的主要内容是Blazor班级管理页面编写和接口对接。
七天.NET 8 操作 SQLite 入门到实战详细教程
EasySQLite 项目源码地址
Blazor简介和快速入门
不熟悉Blazor的同学可以先看这篇文章大概了解一下。
全面的ASP.NET Core Blazor简介和快速入门
前端Table页面和接口对接代码
主要是常见Table的数据展示、数据添加、数据删除、数据修改等操作。
@page "/SchoolClass"
@using Entity
@using WebUI.Common
@inject HttpClient _httpClient;
<Table TItem="SchoolClass"
AutoGenerateColumns="true"
ShowToolbar="true"
IsMultipleSelect="true"
OnSaveAsync="@OnSaveAsync"
OnQueryAsync="@OnQueryAsync"
OnDeleteAsync="@OnDeleteAsync"
IsStriped="true"
IsBordered="true"
ShowSearch="true"
IsPagination="true"
ShowSearchText="true">
<TableColumns>
<TableColumn Sortable="true" Filterable="true" Searchable="true" @bind-Field="@context.ClassName" PlaceHolder="请输入班级名称" />
<TableColumn @bind-Field="@context.ClassID" IsVisibleWhenAdd="false" IsVisibleWhenEdit="false" />
<TableColumn @bind-Field="@context.CreateTime" IsVisibleWhenAdd="false" IsVisibleWhenEdit="false" />
</TableColumns>
<SearchTemplate>
<GroupBox Title="搜索条件">
<div class="row g-3 form-inline">
<div class="col-12 col-sm-6">
<BootstrapInput @bind-Value="@context.ClassName" PlaceHolder="请输入班级名称" maxlength="50" ShowLabel="true" DisplayText="姓名" />
</div>
</div>
</GroupBox>
</SearchTemplate>
</Table>
@code {
/// <summary>
/// 数据查询
/// </summary>
/// <param name="options">options</param>
/// <returns></returns>
private async Task<QueryData<SchoolClass>> OnQueryAsync(QueryPageOptions options)
{
var getClass = new List<SchoolClass>();
var getResults = await _httpClient.GetFromJsonAsync<ApiResponse<List<SchoolClass>>>("api/SchoolClass/GetClass").ConfigureAwait(false);
if (getResults.Success)
{
// 数据模糊过滤筛选
if (!string.IsNullOrWhiteSpace(options.SearchText))
{
getClass = getResults.Data.Where(x => x.ClassName.Contains(options.SearchText)).ToList();
}
else
{
getClass = getResults.Data.ToList();
}
}
//假分页
return await Task.FromResult(new QueryData<SchoolClass>()
{
Items = getClass.Skip((options.PageIndex - 1) * options.PageItems).Take(options.PageItems).ToList(),
TotalCount = getClass.Count()
});
}
/// <summary>
/// 模拟数据增加和修改操作
/// </summary>
/// <param name="studentInfo">studentInfo</param>
/// <param name="changedType">changedType</param>
/// <returns></returns>
public async Task<bool> OnSaveAsync(SchoolClass studentInfo, ItemChangedType changedType)
{
if (changedType.ToString() == "Update")
{
var addResult = await _httpClient.PutAsJsonAsync($"api/SchoolClass/UpdateClass/{studentInfo.ClassID}", studentInfo).ConfigureAwait(false);
if (UtilityBusiness.CheckResponse(addResult))
{
return await Task.FromResult(true);
}
else
{
return await Task.FromResult(false);
}
}
else if (changedType.ToString() == "Add")
{
var addResult = await _httpClient.PostAsJsonAsync("api/SchoolClass/CreateClass", studentInfo).ConfigureAwait(false);
if (UtilityBusiness.CheckResponse(addResult))
{
return await Task.FromResult(true);
}
else
{
return await Task.FromResult(false);
}
}
return await Task.FromResult(true);
}
/// <summary>
/// 数据删除
/// </summary>
/// <param name="items">items</param>
/// <returns></returns>
private async Task<bool> OnDeleteAsync(IEnumerable<SchoolClass> items)
{
var deleteSuccessNum = 0;
var schoolClassList = items.ToList();
foreach (var item in schoolClassList)
{
var delResult = await _httpClient.DeleteAsync($"api/SchoolClass/DeleteClass/{item.ClassID}").ConfigureAwait(false);
if (UtilityBusiness.CheckResponse(delResult))
{
deleteSuccessNum++;
}
}
if (deleteSuccessNum > 0)
{
return await Task.FromResult(true);
}
else
{
return await Task.FromResult(false);
}
}
}
后端API接口
using Entity;
using Microsoft.AspNetCore.Mvc;
using Utility;
namespace WebApi.Controllers
{
/// <summary>
/// 学校班级管理
/// </summary>
[ApiController]
[Route("api/[controller]/[action]")]
public class SchoolClassController : ControllerBase
{
private readonly SQLiteAsyncHelper<SchoolClass> _schoolClassHelper;
/// <summary>
/// 依赖注入
/// </summary>
/// <param name="schoolClassHelper">schoolClassHelper</param>
public SchoolClassController(SQLiteAsyncHelper<SchoolClass> schoolClassHelper)
{
_schoolClassHelper = schoolClassHelper;
}
/// <summary>
/// 班级创建
/// </summary>
/// <param name="schoolClass">创建班级信息</param>
/// <returns></returns>
[HttpPost]
public async Task<ApiResponse<int>> CreateClass([FromBody] SchoolClass schoolClass)
{
try
{
var querySchoolClass = await _schoolClassHelper.QuerySingleAsync(c => c.ClassName == schoolClass.ClassName).ConfigureAwait(false);
if (querySchoolClass != null)
{
return new ApiResponse<int>
{
Success = false,
Message = $"创建班级失败，班级{schoolClass.ClassName}已存在"
};
}
schoolClass.CreateTime = DateTime.Now;
int insertNumbers = await _schoolClassHelper.InsertAsync(schoolClass);
if (insertNumbers > 0)
{
return new ApiResponse<int>
{
Success = true,
Message = "创建班级成功"
};
}
else
{
return new ApiResponse<int>
{
Success = false,
Message = "创建班级失败"
};
}
}
catch (Exception ex)
{
return new ApiResponse<int>
{
Success = false,
Message = ex.Message
};
}
}
/// <summary>
/// 获取所有班级信息
/// </summary>
[HttpGet]
public async Task<ApiResponse<List<SchoolClass>>> GetClass()
{
try
{
var classes = await _schoolClassHelper.QueryAllAsync().ConfigureAwait(false);
return new ApiResponse<List<SchoolClass>>
{
Success = true,
Data = classes
};
}
catch (Exception ex)
{
return new ApiResponse<List<SchoolClass>>
{
Success = false,
Message = ex.Message
};
}
}
/// <summary>
/// 根据班级ID获取班级信息
/// </summary>
/// <param name="classId">班级ID</param>
/// <returns></returns>
[HttpGet("{classId}")]
public async Task<ApiResponse<SchoolClass>> GetClass(int classId)
{
try
{
var schoolClass = await _schoolClassHelper.QuerySingleAsync(c => c.ClassID == classId).ConfigureAwait(false);
if (schoolClass != null)
{
return new ApiResponse<SchoolClass>
{
Success = true,
Data = schoolClass
};
}
else
{
return new ApiResponse<SchoolClass>
{
Success = false,
Message = "班级不存在"
};
}
}
catch (Exception ex)
{
return new ApiResponse<SchoolClass>
{
Success = false,
Message = ex.Message
};
}
}
/// <summary>
/// 更新班级信息
/// </summary>
/// <param name="classId">班级ID</param>
/// <param name="updatedClass">更新的班级信息</param>
/// <returns></returns>
[HttpPut("{classId}")]
public async Task<ApiResponse<int>> UpdateClass(int classId, [FromBody] SchoolClass updatedClass)
{
try
{
var existingClass = await _schoolClassHelper.QuerySingleAsync(c => c.ClassID == classId).ConfigureAwait(false);
if (existingClass != null)
{
existingClass.ClassName = updatedClass.ClassName;
var updateResult = await _schoolClassHelper.UpdateAsync(existingClass).ConfigureAwait(false);
if (updateResult > 0)
{
return new ApiResponse<int>
{
Success = true,
Message = "班级信息更新成功"
};
}
else
{
return new ApiResponse<int>
{
Success = false,
Message = "班级信息更新失败"
};
}
}
else
{
return new ApiResponse<int>
{
Success = false,
Message = "班级不存在"
};
}
}
catch (Exception ex)
{
return new ApiResponse<int>
{
Success = false,
Message = ex.Message
};
}
}
/// <summary>
/// 班级删除
/// </summary>
/// <param name="classId">班级ID</param>
/// <returns></returns>
[HttpDelete("{classId}")]
public async Task<ApiResponse<int>> DeleteClass(int classId)
{
try
{
var deleteResult = await _schoolClassHelper.DeleteAsync(classId).ConfigureAwait(false);
if (deleteResult > 0)
{
return new ApiResponse<int>
{
Success = true,
Message = "班级删除成功"
};
}
else
{
return new ApiResponse<int>
{
Success = true,
Message = "班级删除失败"
};
}
}
catch (Exception ex)
{
return new ApiResponse<int>
{
Success = false,
Message = ex.Message
};
}
}
}
}
接口对接所遇问题及其解决方案
跨源请求 (CORS)问题
在API服务端启用跨源请求 (CORS)：
调用 UseCors 扩展方法并指定 PolicyCorsName CORS 策略。UseCors 添加 CORS 中间件。对 UseCors 的调用必须放在 UseRouting 之后，但在 UseAuthorization 之前。
Program.cs添加如下代码（注意中间件顺序）
var builder = WebApplication.CreateBuilder(args);
var PolicyCorsName = "EasySQLitePolicy";
builder.Services.AddCors(option =>
{
option.AddPolicy(PolicyCorsName, builder =>
{
builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader();
});
});
var app = builder.Build();
app.UseCors(PolicyCorsName);
app.UseAuthorization();
app.MapControllers();
app.Run();
System.Text.Json 反序列化时间异常问题
异常：
Microsoft.AspNetCore.Components.Web.ErrorBoundary[0]
System.Text.Json.JsonException: The JSON value could not be converted to System.DateTime. Path: $.Data[0].CreateTime | LineNumber: 0 | BytePositionInLine: 113.
---> System.FormatException: The JSON value is not in a supported DateTime format.
at System.Text.Json.ThrowHelper.ThrowFormatException(DataType dataType)
at System.Text.Json.Utf8JsonReader.GetDateTime()
at System.Text.Json.Serialization.Converters.DateTimeConverter.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options)
异常原因：
System.Text.Json 时间是认标准的. yyyy-MM-ddTHH:mm:ss 中间得有个T
解决方案：
注释掉服务端对时间日期类型默认格式化处理！
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