Convert DataTable to List T

Question

I have an strongly typed DataTable of type MyType  I d like convert it in a List lt MyType gt    How can I do this    Thanks

User · Answer

Assuming your DataRows inherit from your own type  say MyDataRowType  this should work   List lt MyDataRowType gt  list   new List lt MyDataRowType gt      foreach DataRow row in dataTable Rows        list Add  MyDataRowType row       This is assuming  as you said in a comment  that you re using  NET 2 0 and don t have access to the LINQ extension methods

User · Answer

you can convert your datatable to list  check the following link  https   stackoverflow com a 35171050 1805776  public static class Helper       public static List lt T gt  DataTableToList lt T gt  this DataTable dataTable  where T   new                 var dataList   new List lt T gt                Define what attributes to be read from the class         const System Reflection BindingFlags flags   System Reflection BindingFlags Public   System Reflection BindingFlags Instance             Read Attribute Names and Types         var objFieldNames   typeof T  GetProperties flags  Cast lt System Reflection PropertyInfo gt                 Select item   gt  new                               Name   item Name                  Type   Nullable GetUnderlyingType item PropertyType     item PropertyType                ToList               Read Datatable column names and types         var dtlFieldNames   dataTable Columns Cast lt DataColumn gt                 Select item   gt  new                               Name   item ColumnName                  Type   item DataType                ToList             foreach  DataRow dataRow in dataTable AsEnumerable   ToList                          var classObj   new T                 foreach  var dtField in dtlFieldNames                                System Reflection PropertyInfo propertyInfos   classObj GetType   GetProperty dtField Name                    var field   objFieldNames Find x   gt  x Name    dtField Name                    if  field    null                                         if  propertyInfos PropertyType    typeof DateTime                                                 propertyInfos SetValue                          classObj  convertToDateTime dataRow dtField Name    null                                             else if  propertyInfos PropertyType    typeof Nullable lt DateTime gt                                                  propertyInfos SetValue                          classObj  convertToDateTime dataRow dtField Name    null                                             else if  propertyInfos PropertyType    typeof int                                                 propertyInfos SetValue                          classObj  ConvertToInt dataRow dtField Name    null                                             else if  propertyInfos PropertyType    typeof long                                                 propertyInfos SetValue                          classObj  ConvertToLong dataRow dtField Name    null                                             else if  propertyInfos PropertyType    typeof decimal                                                 propertyInfos SetValue                          classObj  ConvertToDecimal dataRow dtField Name    null                                             else if  propertyInfos PropertyType    typeof String                                                 if  dataRow dtField Name  GetType      typeof DateTime                                                         propertyInfos SetValue                              classObj  ConvertToDateString dataRow dtField Name    null                                                     else                                                       propertyInfos SetValue                              classObj  ConvertToString dataRow dtField Name    null                                                                       else                                                propertyInfos SetValue                              classObj  Convert ChangeType dataRow dtField Name   propertyInfos PropertyType   null                                                                      dataList Add classObj                     return dataList             private static string ConvertToDateString object date                if  date    null              return string Empty           return date    null   string Empty   Convert ToDateTime date  ConvertDate               private static string ConvertToString object value                return Convert ToString ReturnEmptyIfNull value               private static int ConvertToInt object value                return Convert ToInt32 ReturnZeroIfNull value               private static long ConvertToLong object value                return Convert ToInt64 ReturnZeroIfNull value               private static decimal ConvertToDecimal object value                return Convert ToDecimal ReturnZeroIfNull value               private static DateTime convertToDateTime object date                return Convert ToDateTime ReturnDateTimeMinIfNull date               public static string ConvertDate this DateTime datetTime  bool excludeHoursAndMinutes   false                if  datetTime    DateTime MinValue                        if  excludeHoursAndMinutes                  return datetTime ToString  yyyy-MM-dd                return datetTime ToString  yyyy-MM-dd HH mm ss fff                      return null            public static object ReturnEmptyIfNull this object value                if  value    DBNull Value              return string Empty          if  value    null              return string Empty          return value            public static object ReturnZeroIfNull this object value                if  value    DBNull Value              return 0          if  value    null              return 0          return value            public static object ReturnDateTimeMinIfNull this object value                if  value    DBNull Value              return DateTime MinValue          if  value    null              return DateTime MinValue          return value

User · Answer

Try this code and This is easiest way to convert datatable to list  List lt DataRow gt  listtablename   dataTablename AsEnumerable   ToList

User · Answer

The following does it in a single line   dataTable Rows OfType lt DataRow gt         Select dr   gt  dr Field lt MyType gt  columnName   ToList       Edit   Add a reference to System Data DataSetExtensions to your project if this does not compile

User · Answer

There are Linq extension methods for DataTable   Add reference to  System Data DataSetExtensions dll  Then include the namespace  using System Data DataSetExtensions  Finally you can use Linq extensions on DataSet and DataTables   var matches   myDataSet Tables First   Where dr  gt dr Field lt int gt   id      1     On  Net 2 0 you can still add generic method   public static List lt T gt  ConvertRowsToList lt T gt   DataTable input  Convert lt DataRow  T gt  conversion        List lt T gt  retval   new List lt T gt        foreach DataRow dr in input Rows          retval Add  conversion dr          return retval

User · Answer

please try this code   public List lt T gt  ConvertToList lt T gt  DataTable dt        var columnNames   dt Columns Cast lt DataColumn gt             Select c   gt  c ColumnName           ToList        var properties   typeof T  GetProperties        return dt AsEnumerable   Select row   gt                var objT   Activator CreateInstance lt T gt             foreach  var pro in properties                        if  columnNames Contains pro Name                   pro SetValue objT  row pro Name                      return objT         ToList

User · Answer

List lt MyType gt  listName   dataTableName AsEnumerable   Select m   gt  new MyType        ID   m Field lt string gt   ID       Description   m Field lt string gt   Description       Balance   m Field lt double gt   Balance       ToList

User · Answer

That pretty works   I made some updates from  suneelsarraf s answer and I removed Convert ChangeType   because it keeps throwing Invalid Cast Exception  Have a take a look   region     Convert DT to List lt Object gt           private List lt I gt  ConvertTo lt I gt  DataTable datatable  where I   class               List lt I gt  lstRecord   new List lt I gt             try                       List lt string gt  columnsNames   new List lt string gt                 foreach  DataColumn DataColumn in datatable Columns                  columnsNames Add DataColumn ColumnName               lstRecord   datatable AsEnumerable   ToList   ConvertAll lt I gt  row   gt  GetObject lt I gt  row  columnsNames                return lstRecord                    catch                       return lstRecord                        private I GetObject lt I gt  DataRow row  List lt string gt  columnsName  where I   class               I obj    I Activator CreateInstance typeof I            try                       PropertyInfo   Properties   typeof I  GetProperties                foreach  PropertyInfo objProperty in Properties                                string columnname   columnsName Find name   gt  name ToLower      objProperty Name ToLower                     if   string IsNullOrEmpty columnname                                         object dbValue   row columnname                       if  dbValue    DBNull Value                                                if  Nullable GetUnderlyingType objProperty PropertyType     null                                                        objProperty SetValue obj  Convert ChangeType dbValue  Type GetType Nullable GetUnderlyingType objProperty PropertyType  ToString      null                                                     else                                                       objProperty SetValue obj  Convert ChangeType dbValue  Type GetType objProperty PropertyType ToString      null                                                                                               return obj                    catch Exception ex                        return obj                        endregion  And this is how you use in your code     Other Codes Here var lstResult   ConvertTo lt TEntity gt  dataTableName      Convert DT to List lt TEntity gt   Have Fun  Be Safe in 2020

User · Answer

There is a little example that you can use               DataTable dt   GetCustomersDataTable null                            IEnumerable lt SelectListItem gt  lstCustomer   dt AsEnumerable   Select x   gt  new SelectListItem                                 Value   x Field lt string gt   CustomerId                    Text   x Field lt string gt   CustomerDescription                  ToList                 return lstCustomer

User · Answer

IEnumerable lt DataRow gt  rows   dataTable AsEnumerable     System Data DataSetExtensions dll  IEnumerable lt DataRow gt  rows   dataTable Rows OfType lt DataRow gt      System Core dll

User · Answer

The method ConvertToList that is posted below and uses reflection works perfectly for me  Thanks   I made a slight modification to make it work with conversions on the T property types   public List lt T gt  ConvertToList lt T gt  DataTable dt        var columnNames   dt Columns Cast lt DataColumn gt                 Select c   gt  c ColumnName               ToList        var properties   typeof T  GetProperties        return dt AsEnumerable   Select row   gt                var objT   Activator CreateInstance lt T gt             foreach  var pro in properties                        if  columnNames Contains pro Name                                  PropertyInfo pI   objT GetType   GetProperty pro Name                    pro SetValue objT  row pro Name     DBNull Value   null   Convert ChangeType row pro Name   pI PropertyType                                    return objT        ToList        Hope it helps  Regards

User · Answer

thanks for all of posts      I have done it with using Linq Query  to view this please visit the following link  http   codenicely blogspot com 2012 02 converting-your-datatable-into-list html

User · Answer

Data table to List       region  getobject filled object with property reconized       public List lt T gt  ConvertTo lt T gt  DataTable datatable  where T   new                 List lt T gt  Temp   new List lt T gt             try                       List lt string gt  columnsNames   new List lt string gt                 foreach  DataColumn DataColumn in datatable Columns                  columnsNames Add DataColumn ColumnName               Temp   datatable AsEnumerable   ToList   ConvertAll lt T gt  row   gt  getObject lt T gt  row  columnsNames                return Temp                    catch                       return Temp                       public T getObject lt T gt  DataRow row  List lt string gt  columnsName  where T   new                 T obj   new T            try                       string columnname                   string value                   PropertyInfo   Properties              Properties   typeof T  GetProperties                foreach  PropertyInfo objProperty in Properties                                columnname   columnsName Find name   gt  name ToLower      objProperty Name ToLower                     if   string IsNullOrEmpty columnname                                         value   row columnname  ToString                        if   string IsNullOrEmpty value                                                 if  Nullable GetUnderlyingType objProperty PropertyType     null                                                        value   row columnname  ToString   Replace          Replace                                       objProperty SetValue obj  Convert ChangeType value  Type GetType Nullable GetUnderlyingType objProperty PropertyType  ToString      null                                                     else                                                       value   row columnname  ToString   Replace                                       objProperty SetValue obj  Convert ChangeType value  Type GetType objProperty PropertyType ToString      null                                                                                               return obj                    catch                       return obj                        endregion   IEnumerable collection To Datatable       region  New DataTable      public DataTable ToDataTable lt T gt  IEnumerable lt T gt  collection                DataTable newDataTable   new DataTable            Type impliedType   typeof T           PropertyInfo    propInfo   impliedType GetProperties            foreach  PropertyInfo pi in  propInfo              newDataTable Columns Add pi Name  pi PropertyType            foreach  T item in collection                        DataRow newDataRow   newDataTable NewRow                newDataRow BeginEdit                foreach  PropertyInfo pi in  propInfo                  newDataRow pi Name    pi GetValue item  null               newDataRow EndEdit                newDataTable Rows Add newDataRow                     return newDataTable

User · Answer

Create a list with type lt DataRow gt  by extend the datatable with AsEnumerable call       var mylist   dt AsEnumerable   ToList      Cheers   Happy Coding

[c#] Convert DataTable to List<T>

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