देखें

Question

में HiddenFor IEnumerable बनाना मैं एक संपत्ति है कि एक IEnumerable

public IEnumerable<string> ChangesOthersResult { get; set; } 

मैं एक दृश्य वापस नियंत्रक से ChangesOthersResult और पद से सभी मूल्यों को इकट्ठा करने की जरूरत है। मैं Ienumerable के माध्यम से कैसे लूप कर सकता हूं और छिपे हुए फ़ील्ड बना सकता हूं जो नियंत्रक में ViewModel पर वापस बंधेगा?

foreach(var item in Model.ChangesOthersResult) 
    { 
     @Html.HiddenFor(x => x.ChangesOthersResult); 
    } 

मुझे कच्चे SQL कथन को टेक्स्ट के रूप में दे रहा है।

Answer 1

Convert ChangesOthersResult एक सरणी के लिए इस्तेमाल करते हैं और उत्पादन कुछ करने के लिए पाश के लिए एक का उपयोग इस तरह:

for (int i = 0; i < Model.ChangesOthersResult.Length; i++)  
{ 
    @Html.Hidden("ChangesOthersResult[" + i + "]", Model.ChangesOthersResult[i]) 
} 

Answer 2

अपने मॉडल के निर्माता में, नए IEnumerable ChagesOthersResult

public Model() 
{ 
    ChangesOthersResult = new List<string>(); 
} 

तब ध्यान में रखते हुए, एक पाश के लिए

for(int i = 0; i < Model.ChangesOthersResult.Count; i++) 
{ 
    @Html.HiddenFor(x => x.ChangesOthersResult[i]) 
} 

Answer 3

मैंने इसे एक विस्तार विधि में बनाया ताकि पाश आपके विचार कोड तोड़कर बिगाड़ना नहीं करता है:

public static string GetMemberName<TModel, T>(this Expression<Func<TModel, T>> input) 
    { 
     if (input == null) 
      return null; 

     if (input.Body.NodeType != ExpressionType.MemberAccess) 
      return null; 

     var memberExp = input.Body as MemberExpression; 
     return memberExp != null ? memberExp.Member.Name : null; 
    } 

आशा इस उपयोगी है:

public static class HiddenExtensions 
{ 
    public static MvcHtmlString HiddenForEnumerable<TModel, TProperty>(this HtmlHelper<TModel> helper, 
     Expression<Func<TModel, IEnumerable<TProperty>>> expression) 

    { 
     var sb = new StringBuilder(); 

     var membername = expression.GetMemberName(); 
     var model = helper.ViewData.Model; 
     var list = expression.Compile()(model); 

     for (var i = 0; i < list.Count(); i++) 
     { 
      sb.Append(helper.Hidden(string.Format("{0}[{1}]", membername, i), list.ElementAt(i))); 
     } 

     return new MvcHtmlString(sb.ToString()); 
    } 
} 

GetMemberName एक और विस्तार विधि है।

Answer 4

.EEach() का उपयोग नहीं कर सकता है, क्योंकि @ Html.HiddenFor (x => x.ChangesOthersResult) एक ही तत्व आईडी बना देगा, जिसे मॉडल पोस्टबैक पर पहचाना नहीं जाएगा।

for (int i = 0; i < Model.ChangesOthersResult.Count(); i++)  
{ 
    @Html.HiddenFor(x => x.ChangesOthersResult[I]); 
} 

Answer 5

विस्तारित @GitteTitter के कस्टम वस्तुओं की सूची के लिए समाधान:

@Html.HiddenForEnumerable(x => x.ValueTypes)  
@Html.HiddenForEnumerable(x => x.ViewModels, h=>h.Id, h=>h.Name) 
@Html.HiddenForEnumerable(x => x.ViewModels, allPublicProps: true) 

स्रोत:

/// <summary> 
/// Returns hiddens for every IEnumerable item, with it's selected properties, if any memberPropsExpression provided. 
/// </summary> 
public static MvcHtmlString HiddenForEnumerable<TModel, TModelProperty>(this HtmlHelper<TModel> helper, 
    Expression<Func<TModel, IEnumerable<TModelProperty>>> expression, params Expression<Func<TModelProperty, object>>[] memberPropsExpressions) 
{ 
    var sb = new StringBuilder(); 

    var membername = expression.GetMemberName(); 
    var model = helper.ViewData.Model; 
    var list = expression.Compile()(model); 

    var memPropsInfo = memberPropsExpressions.Select(x => new 
    { 
     MemberPropName = x.GetMemberName(), 
     ListItemPropGetter = x.Compile() 
    }).ToList(); 

    for (var i = 0; i < list.Count(); i++) 
    { 
     var listItem = list.ElementAt(i); 
     if (memPropsInfo.Any()) 
     { 
      foreach (var q in memPropsInfo) 
      { 
       sb.Append(helper.Hidden(string.Format("{0}[{1}].{2}", membername, i, q.MemberPropName), q.ListItemPropGetter(listItem))); 
      } 
     } 
     else 
     { 
      sb.Append(helper.Hidden(string.Format("{0}[{1}]", membername, i), listItem)); 
     } 
    } 

    return new MvcHtmlString(sb.ToString()); 
} 

/// <summary> 
/// Returns hiddens for every IEnumerable item, with it's all public writable properties, if allPublicProps set to true. 
/// </summary> 
public static MvcHtmlString HiddenForEnumerable<TModel, TModelProperty>(this HtmlHelper<TModel> helper, 
    Expression<Func<TModel, IEnumerable<TModelProperty>>> expression, bool allPublicProps) 
{ 
    if (!allPublicProps) 
     return HiddenForEnumerable(helper, expression); 

    var sb = new StringBuilder(); 

    var membername = expression.GetMemberName(); 
    var model = helper.ViewData.Model; 
    var list = expression.Compile()(model); 

    var type = typeof(TModelProperty); 
    var memPropsInfo = type.GetProperties(BindingFlags.Public | BindingFlags.Instance) 
     .Where(x => x.GetSetMethod(false) != null && x.GetGetMethod(false) != null) 
     .Select(x => new 
     { 
      MemberPropName = x.Name, 
      ListItemPropGetter = (Func<TModelProperty, object>)(p => x.GetValue(p, null)) 
     }).ToList(); 

    if (memPropsInfo.Count == 0) 
     return HiddenForEnumerable(helper, expression); 

    for (var i = 0; i < list.Count(); i++) 
    { 
     var listItem = list.ElementAt(i); 
     foreach (var q in memPropsInfo) 
     { 
      sb.Append(helper.Hidden(string.Format("{0}[{1}].{2}", membername, i, q.MemberPropName), q.ListItemPropGetter(listItem))); 
     } 
    } 

    return new MvcHtmlString(sb.ToString()); 
} 

public static string GetMemberName<TModel, T>(this Expression<Func<TModel, T>> input) 
{ 
    if (input == null) 
     return null; 

    MemberExpression memberExp = null; 

    if (input.Body.NodeType == ExpressionType.MemberAccess) 
     memberExp = input.Body as MemberExpression; 
    else if (input.Body.NodeType == ExpressionType.Convert) 
     memberExp = ((UnaryExpression)input.Body).Operand as MemberExpression; 

    return memberExp != null ? memberExp.Member.Name : null; 
} 

Answer 6

कैसे एक पुनरावर्ती दृष्टिकोण के बारे में?

public static MvcHtmlString HiddenForEnumerable<TModel, TModelProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, IEnumerable<TModelProperty>>> expression, string prefix = null) 
{ 
    var sb = new StringBuilder(); 

    var membername = expression.GetMemberName(); 
    var model = htmlHelper.ViewData.Model; 
    var list = expression.Compile()(model); 

    var type = typeof(TModelProperty); 
    var memPropertyInfo = type.GetProperties(BindingFlags.Public | BindingFlags.Instance) 
     .Where(x => x.GetSetMethod(false) != null && x.GetGetMethod(false) != null) 
     .Select(x => new 
     { 
      Type = x.PropertyType, 
      x.Name, 
      Get = (Func<TModelProperty, object>)(p => x.GetValue(p, null)) 
     }).ToList(); 

    for (var i = 0; i < list.Count(); i++) 
    { 
     var listItem = list.ElementAt(i); 
     if (memPropertyInfo.Any()) 
     { 
      foreach (var m in memPropertyInfo) 
      { 
       var inputName = $"{prefix ?? ""}{membername}[{i}].{m.Name}"; 
       var inputValue = m.Get(listItem); 
       var genericArguments = m.Type.GetGenericArguments(); 

       if (genericArguments.Any() && IsEnumerableType(m.Type)) 
       { 
        var delegateType = typeof(Func<,>).MakeGenericType(typeof(TModel), m.Type); 
        var bodyExpression = Expression.Constant(inputValue, m.Type); 
        var paramExpression = Expression.Parameter(typeof(TModel), "model"); 
        var expressionTree = Expression.Lambda(delegateType, bodyExpression, new[] { paramExpression }); 
        var hiddenForEnumerableInfo = typeof(HtmlHelpers).GetMethod("HiddenForEnumerable"); 
        var hiddenForEnumerable = hiddenForEnumerableInfo.MakeGenericMethod(typeof(TModel), genericArguments[0]); 
        object[] args = { htmlHelper, expressionTree, inputName }; 

        sb.Append(hiddenForEnumerable.Invoke(null, args)); 
       } 
       else 
       { 
        sb.Append(htmlHelper.Hidden(inputName, inputValue)); 
       } 
      } 
     } 
     else 
     { 
      sb.Append(htmlHelper.Hidden($"{membername}[{i}]", listItem)); 
     } 
    } 

    return new MvcHtmlString(sb.ToString()); 
} 

private static string GetMemberName<TModel, T>(this Expression<Func<TModel, T>> input) 
{ 
    if (input == null) 
     return null; 

    MemberExpression memberExp = null; 

    if (input.Body.NodeType == ExpressionType.MemberAccess) 
     memberExp = input.Body as MemberExpression; 
    else if (input.Body.NodeType == ExpressionType.Convert) 
     memberExp = ((UnaryExpression)input.Body).Operand as MemberExpression; 

    return memberExp?.Member.Name; 
} 

private static bool IsEnumerableType(Type type) 
{ 
    return (type.GetInterface("IEnumerable") != null); 
} 

उदाहरण:

public class Model 
{ 
    IEnumerable<Order> Orders { get; set; } 
} 

public class Order 
{ 
    public int OrderId { get; set; } 
    IEnumerable<Item> Items { get; set; } 
} 

public class Item 
{ 
    public int ItemId { get; set; } 
    public string Name { get; set; } 
} 

उपयोग:

@Html.HiddenForEnumerable(model => model.Orders) 

आउटपुट:

<input id="Orders_0__OrderId" name="Orders[0].OrderId" type="hidden" value="1001"> 
<input id="Orders_0__Items_0__ItemId" name="Orders[0].Items[0].ItemId" type="hidden" value="201"> 
<input id="Orders_0__Items_0__Name" name="Orders[0].Items[0].Name" type="hidden" value="Something1"> 
<input id="Orders_0__Items_1__ItemId" name="Orders[0].Items[1].ItemId" type="hidden" value="202"> 
<input id="Orders_0__Items_1__Name" name="Orders[0].Items[1].Name" type="hidden" value="Something2"> 
<input id="Orders_1__OrderId" name="Orders[1].OrderId" type="hidden" value="1002"> 
<input id="Orders_1__Items_0__ItemId" name="Orders[1].Items[0].ItemId" type="hidden" value="205"> 
<input id="Orders_1__Items_0__Name" name="Orders[1].Items[0].Name" type="hidden" value="Something5"> 

Answer 7

aspnetcore के लिए एक ही

using Microsoft.AspNetCore.Html; 
using Microsoft.AspNetCore.Mvc.Rendering; 
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Linq.Expressions; 
using System.Reflection; 
using System.Text; 

namespace Proj.Helpers 
{ 
    public static class HtmlHelpers 
    { 
     public static IHtmlContent HiddenForEnumerable<TModel, TModelProperty>(this IHtmlHelper<TModel> helper, 
    Expression<Func<TModel, IEnumerable<TModelProperty>>> expression, params Expression<Func<TModelProperty, object>>[] memberPropsExpressions) 
     { 
      var hcb = new HtmlContentBuilder(); 

      var membername = expression.GetMemberName(); 
      var model = helper.ViewData.Model; 
      var list = expression.Compile()(model); 

      var memPropsInfo = memberPropsExpressions.Select(x => new 
      { 
       MemberPropName = x.GetMemberName(), 
       ListItemPropGetter = x.Compile() 
      }).ToList(); 

      for (var i = 0; i < list.Count(); i++) 
      { 
       var listItem = list.ElementAt(i); 
       if (memPropsInfo.Any()) 
       { 
        foreach (var q in memPropsInfo) 
        { 
         hcb.AppendHtml(helper.Hidden(string.Format("{0}[{1}].{2}", membername, i, q.MemberPropName), q.ListItemPropGetter(listItem))); 
        } 
       } 
       else 
       { 
        hcb.AppendHtml(helper.Hidden(string.Format("{0}[{1}]", membername, i), listItem)); 
       } 
      } 

      return hcb; 
     } 

     /// <summary> 
     /// Returns hiddens for every IEnumerable item, with it's all public writable properties, if allPublicProps set to true. 
     /// </summary> 
     public static IHtmlContent HiddenForEnumerable<TModel, TModelProperty>(this IHtmlHelper<TModel> helper, 
      Expression<Func<TModel, IEnumerable<TModelProperty>>> expression, bool allPublicProps) 
     { 
      if (!allPublicProps) 
       return HiddenForEnumerable(helper, expression); 

      var hcb = new HtmlContentBuilder(); 

      var membername = expression.GetMemberName(); 
      var model = helper.ViewData.Model; 
      var list = expression.Compile()(model); 

      var type = typeof(TModelProperty); 
      var memPropsInfo = type.GetProperties(BindingFlags.Public | BindingFlags.Instance) 
       .Where(x => x.GetSetMethod(false) != null && x.GetGetMethod(false) != null) 
       .Select(x => new 
       { 
        MemberPropName = x.Name, 
        ListItemPropGetter = (Func<TModelProperty, object>)(p => x.GetValue(p, null)) 
       }).ToList(); 

      if (memPropsInfo.Count == 0) 
       return HiddenForEnumerable(helper, expression); 

      for (var i = 0; i < list.Count(); i++) 
      { 
       var listItem = list.ElementAt(i); 
       foreach (var q in memPropsInfo) 
       { 
        hcb.AppendHtml(helper.Hidden(string.Format("{0}[{1}].{2}", membername, i, q.MemberPropName), q.ListItemPropGetter(listItem))); 
       } 
      } 

      return hcb; 
     } 

     public static string GetMemberName<TModel, T>(this Expression<Func<TModel, T>> input) 
     { 
      if (input == null) 
       return null; 

      MemberExpression memberExp = null; 

      if (input.Body.NodeType == ExpressionType.MemberAccess) 
       memberExp = input.Body as MemberExpression; 
      else if (input.Body.NodeType == ExpressionType.Convert) 
       memberExp = ((UnaryExpression)input.Body).Operand as MemberExpression; 

      return memberExp != null ? memberExp.Member.Name : null; 
     } 
    } 
}