LINQ多表连接（MVC C#）代码错误排查及解决方案求助

Hey there! Let's dig into potential issues in your ViewModel code and work through fixes step by step.

1. 数值型属性误用string类型 #

Your LeaveBalance and PreviousBalance properties (which represent numeric values) are currently defined as string—this creates unnecessary headaches:

• Frontend display/ calculations will break (you can't easily add/subtract string values)
• Backend processing requires extra type conversions, which risk throwing exceptions
• You can't use data annotations to validate numeric ranges (like preventing negative balances)

Fix: Switch these properties to a numeric type like decimal (for fractional balances) or int (for whole-day leave):

public class LeaveInitialBalanceViewModelKendoGrid 
{ 
    [HiddenKendoGridColumn] 
    public string ID { get; set; } 
    public string EmployeeCode { get; set; } 
    public string EmployeeName { get; set; } 
    public string Department { get; set; } 
    public string Section { get; set; } 
    public string LeaveType { get; set; } 
    // Use decimal for balances that might include fractions
    public decimal LeaveBalance { get; set; } 
    public decimal PreviousBalance { get; set; } 
    // Or use int if leave is tracked in whole days only
    // public int LeaveBalance { get; set; }
}

2. Missing Data Annotations (Optional but Highly Recommended) #

If this ViewModel is used for form submissions with Kendo Grid, add data annotations to enforce validation and improve UX:

using System.ComponentModel.DataAnnotations;

public class LeaveInitialBalanceViewModelKendoGrid 
{ 
    [HiddenKendoGridColumn] 
    public string ID { get; set; } 

    [Required(ErrorMessage = "Employee code is required")]
    [MaxLength(20)]
    public string EmployeeCode { get; set; } 

    [Required(ErrorMessage = "Employee name is required")]
    [MaxLength(50)]
    public string EmployeeName { get; set; } 

    public string Department { get; set; } 
    public string Section { get; set; } 

    [Required(ErrorMessage = "Leave type is required")]
    public string LeaveType { get; set; } 

    [Range(0, double.MaxValue, ErrorMessage = "Balance cannot be negative")]
    public decimal LeaveBalance { get; set; } 

    [Range(0, double.MaxValue, ErrorMessage = "Previous balance cannot be negative")]
    public decimal PreviousBalance { get; set; } 
}

3. Truncated Code Cleanup #

Your code cuts off at PreviousBalance { get;...}—make sure to:

• Finish defining all properties with complete get/set accessors (use get; init; for read-only properties if needed)
• Close all curly braces and fix any syntax errors from the truncated section

Quick Side Note #

Double-check that your custom [HiddenKendoGridColumn] attribute is properly implemented and recognized by the Kendo Grid framework—if not, the ID column might still render on the frontend.

内容的提问来源于stack exchange，提问作者Søśø ÐålợȜà ZåȜră