Question

我有这段代码：

IDictionary<string, IEnumerable<object>> setValues = new Dictionary<string, IEnumerable<object>>()
{
   { "IN_PARTENER", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_PARTENER"]) }, 
   { "IN_DATA", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_DATA"]) }, 
   { "IN_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_VALOARE"]) }, 
   { "OUT_PARTENER", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_PARTENER"]) }, 
   { "OUT_DATA", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_DATA"]) }, 
   { "OUT_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_VALOARE"]) },
   { "TOTAL_ZI", dtResult.Rows.Cast<DataRow>().Select(row => row["TOTAL_ZI"]) },
};

我想将字符串IN_VALOARE和OUT_VALOARE从string转换为decimal，但我不知道该怎么做

Answer 1

您可以在Select：

中执行此操作

.Select(row => (decimal)row["IN_VALOARE"])

完整代码：

IDictionary<string, IEnumerable<object>> setValues = new Dictionary<string, IEnumerable<object>>()
{
   { "IN_PARTENER", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_PARTENER"]) }, 
   { "IN_DATA", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_DATA"]) }, 
   { "IN_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => (decimal)row["IN_VALOARE"]) }, 
   { "OUT_PARTENER", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_PARTENER"]) }, 
   { "OUT_DATA", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_DATA"]) }, 
   { "OUT_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => (decimal)row["OUT_VALOARE"]) },
   { "TOTAL_ZI", dtResult.Rows.Cast<DataRow>().Select(row => row["TOTAL_ZI"]) },
};

由于你不能用不同的值类型创建一个字典（没有得到hacky），或许你应该看一下使用自定义类：

public class MyThing
{
    public string InPartener { get; set; }
    public string InData { get; set; }
    public decimal InValoare { get; set; }
    public string OutPartener { get; set; }
    public string OutData { get; set; }
    public decimal OutValoare { get; set; }
    public string TotalZi { get; set; }
}

列出这些课程：

var myThings = dtResult.Rows.Cast<DataRow>().Select(r => new MyThing
{
    InPartener = r["IN_PARTENER"],
    InData = r["IN_DATA"],
    InValoare = (decimal)r["IN_VALOARE"],
    OutPartener = r["OUT_PARTENER"],
    OutData = r["OUT_DATA"],
    OutValoare = (decimal)r["OUT_VALOARE"],
    TotalZi = r["TOTAL_ZI"]
};

Answer 2

您可以在decimal.Parse部分

的选择内添加IN_VALOARE

 { "IN_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => decimal.Parse(row["IN_VALOARE"].ToString())) },

给出了

 IDictionary<string, IEnumerable<object>> setValues = new Dictionary<string, IEnumerable<object>>()
        {
           { "IN_PARTENER", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_PARTENER"]) }, 
           { "IN_DATA", dtResult.Rows.Cast<DataRow>().Select(row => row["IN_DATA"]) }, 
           { "IN_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => decimal.Parse(row["IN_VALOARE"].ToString())) }, 
           { "OUT_PARTENER", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_PARTENER"]) }, 
           { "OUT_DATA", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_DATA"]) }, 
           { "OUT_VALOARE", dtResult.Rows.Cast<DataRow>().Select(row => row["OUT_VALOARE"]) },
           { "TOTAL_ZI", dtResult.Rows.Cast<DataRow>().Select(row => row["TOTAL_ZI"]) },
        };

Answer 3

首先，如果需要IEnumerable<object>，那么您实际上并不需要将字段值转换为十进制或其他类型。

其次，如果您需要获取字典中的所有列，那么您的所有代码都可以简化为：

var setValues = dtResult.Columns.Cast<DataColumn>()
       .ToDictionary(c => c.ColumnName, 
                     c => dtResult.AsEnumerable().Select(r => r.Field<object>(c)));

简单 - 获取所有列，然后创建字典，列名为键，列值集合为值。

注意：这取决于您的需求，但也考虑使用强类型实体而不是字典，字符串和对象。即定义实体

public class Transaction // chose good name here
{
    public string InPartener { get; set; }
    public string InData { get; set; }
    public decimal InValoare { get; set; }
    public string OutParener { get; set; }
    public string OutData { get; set; }
    public decimal OutValoare { get; set; } 
    public string TotalZi { get; set; }
}

使用LINQ to DataSet将DataTable转换为强类型对象的集合：

 var transactions = from r in dtResult.AsEnumerable()
                    select new Transaction {
                       InPartener = r.Field<string>("IN_PARTENER"),
                       InData = r.Field<string>("IN_DATA"),
                       InValoare = r.Field<decimal>("IN_VALOARE"),
                       OutPartener = r.Field<string>("OUT_PARTENER"),
                       OutData = r.Field<string>("OUT_DATA"),
                       OutValoare = r.Field<decimal>("OUT_VALOARE"),
                       TotalZi = r.Field<string>("TOTAL_ZI")
                    };

这将为您提供具有内部意义支持的强大类型的商业模式。例如。如果你需要计算总InValoare：

  decimal total = transactions.Sum(t => t.InValoare);

从IEnumerable <object>转换为IEnumerable <decimal>

3 个答案: