Conversion of List to DataTable

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Hi,

I want to know something about Conversion of List<object> to DataTable.
I have searched for it on Google and Codeproject and found some article but every article says to iterate the List which I have already implemented.

Now, I want to know, is there any other better way to do this?
If any body can help me then it would be great for me.

Thanks in advance.

Regards
AR

Posted 29-Apr-11 22:18pm

Ankit Rajput

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Comments

wizardzz 4-May-11 13:37pm

Why can't you iterate? I mean, out of curiosity, how would you expect to do this? Any conversion function would be iterating under the hood I think.

Ankit Rajput 4-May-11 15:06pm

I have already implemented the iteration into my project and released to production.
Now to update my knowledge or you can say to find another way or better way to do something, I have raised this question.

wizardzz 4-May-11 15:10pm

Well, you could post your code and we can tell you if there's anything inefficient. But why don't you like iterating?

5 solutions

Solution 1

try this
http://stackoverflow.com/questions/564366/generic-list-to-datatable[^]

Posted 29-Apr-11 22:44pm

ambarishtv

Comments

Ankit Rajput 30-Apr-11 6:06am

This one is the same method. We need to iterate in ToDataTable function. and I dont want to iterate in my code.

Ankit Rajput 30-Apr-11 6:06am

By the way Thanks

Solution 2

Try this
Link1-[Convert Generic List In To DataTable][^]
Link2-[Convert Generic List To DataTable][^]

Posted 29-Apr-11 23:13pm

RaviRanjanKr

Comments

Ankit Rajput 30-Apr-11 6:07am

This one is the same method. We need to iterate in ToDataTable function. and I dont want to iterate in my code.

By the Thanks

Dave Kreskowiak 4-May-11 7:13am

You don't hvae a choice. There is no way to convert a List to a DataTable without converting each item, one at a time, manually.

AspDotNetDev 4-May-11 13:41pm

True, though one may be able to amortize the conversion using a derived version of DataTable.

Solution 5

The Solution 4 is perfect!!!
I did the convertion into VB. For whom wants:

VB

''' <summary>
''' Converts a Generic List into a DataTable.
''' </summary>
''' <param name="genericList"></param>
''' <returns></returns>
''' <remarks></remarks>
Public Shared Function ConvertGenericListToDataTable(ByVal genericList As Object) As Data.DataTable

    Dim dataTable As Data.DataTable = Nothing
    Dim listType As Type = genericList.GetType()

    If (listType.IsGenericType AndAlso (genericList IsNot Nothing)) Then

        '//determine the underlying type the List<> contains
        Dim elementType As Type = listType.GetGenericArguments()(0)

        '//create empty table -- give it a name in case
        '//it needs to be serialized
        dataTable = New Data.DataTable(elementType.Name + "List")

        '//define the table -- add a column for each public
        '//property or field
        Dim memberInfos As MemberInfo() = elementType.GetMembers(BindingFlags.Public Or BindingFlags.Instance)
        For Each memberInfo As MemberInfo In memberInfos

            If (memberInfo.MemberType = MemberTypes.Property) Then

                Dim propertyInfo As PropertyInfo = CType(memberInfo, PropertyInfo)

                If IsNullableType(propertyInfo.PropertyType) Then
                    dataTable.Columns.Add(propertyInfo.Name, New ComponentModel.NullableConverter(propertyInfo.PropertyType).UnderlyingType)
                Else
                    dataTable.Columns.Add(propertyInfo.Name, propertyInfo.PropertyType)
                End If
            ElseIf (memberInfo.MemberType = MemberTypes.Field) Then
                Dim fieldInfo As FieldInfo = CType(memberInfo, FieldInfo)
                dataTable.Columns.Add(fieldInfo.Name, fieldInfo.FieldType)
            End If
        Next

        '//populate the table
        Dim listData As IList = CType(genericList, IList)
        For Each record As Object In listData
            Dim index As Integer = 0
            Dim fieldValues(dataTable.Columns.Count - 1) As Object ' = CType(New Object(), Object())
            For Each columnData As Data.DataColumn In dataTable.Columns
                Dim memberInfo As MemberInfo = elementType.GetMember(columnData.ColumnName)(0)
                If memberInfo.MemberType = MemberTypes.Property Then
                    Dim propertyInfo As PropertyInfo = CType(memberInfo, PropertyInfo)
                    fieldValues(index) = propertyInfo.GetValue(record, Nothing)
                ElseIf memberInfo.MemberType = MemberTypes.Field Then
                    Dim fieldInfo As FieldInfo = CType(memberInfo, FieldInfo)
                    fieldValues(index) = fieldInfo.GetValue(record)
                End If
                index += 1
            Next
            dataTable.Rows.Add(fieldValues)
        Next

    End If

    Return dataTable
End Function

''' <summary>
''' Check if a type is Nullable type
''' </summary>
''' <param name="propertyType"></param>
''' <returns></returns>
''' <remarks></remarks>
Private Shared Function IsNullableType(ByVal propertyType As Type) As Boolean

    Return (propertyType.IsGenericType) AndAlso (propertyType.GetGenericTypeDefinition() Is GetType(Nullable(Of )))

End Function

Posted 5-Nov-12 7:40am

fabiops

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AspDotNetDev · Accepted Answer · 2011-05-04T07:40:00

Why do you want to avoid iteration?

If it is to reduce code, use LINQ (technically still iterates, but looks less like it's doing that):

C#

List<object> x = new List<object>();
DataTable d = new DataTable();
d.Columns.Add("item");
x.ForEach((item) => d.Rows.Add(item));

If you want to avoid the immediate performance hit of processing each item, you can derive a class from DataTable that wraps a List internally:

C#

public class MyDataTable<T> : DataTable
{
    private List<T> internalList { get; set; }
    public MyDataTable(List<T> p_internalList)
    {
        this.internalList = p_internalList;
    }
    //TODO: Your implementation here.
}

Pretty sure that wrapping technique is also used with the ReadOnlyCollection returned from List.AsReadOnly().

Wonde Tadesse · Accepted Answer · 2011-05-06T15:53:00

Here is the full functioning code. It consider all the list object datatype and even check Nullable.

C#

/// <summary>
/// Converts a Generic List into a DataTable.
/// </summary>
/// <param name="genericList">Generic list</param>
/// <returns>DataTable object</returns>
private static DataTable GenericListToDataTable(object genericList)
{
    DataTable dataTable = null;
    Type listType = genericList.GetType();

    if (listType.IsGenericType & (genericList != null)) {
        //determine the underlying type the List<> contains
        Type elementType = listType.GetGenericArguments()[0];

        //create empty table -- give it a name in case
        //it needs to be serialized
        dataTable = new DataTable(elementType.Name + "List");

        //define the table -- add a column for each public
        //property or field
        MemberInfo[] memberInfos = elementType.GetMembers(BindingFlags.Public | BindingFlags.Instance);
        foreach (MemberInfo memberInfo in memberInfos) {
            if (memberInfo.MemberType == MemberTypes.Property) {
                PropertyInfo propertyInfo = memberInfo as PropertyInfo;
                if (IsNullableType(propertyInfo.PropertyType)) {
                    dataTable.Columns.Add(propertyInfo.Name, new NullableConverter(propertyInfo.PropertyType).UnderlyingType);
                } else {
                    dataTable.Columns.Add(propertyInfo.Name, propertyInfo.PropertyType);
                }
            } else if (memberInfo.MemberType == MemberTypes.Field) {
                FieldInfo fieldInfo = memberInfo as FieldInfo;
                dataTable.Columns.Add(fieldInfo.Name, fieldInfo.FieldType);
            }
        }

        //populate the table
        IList listData = genericList as IList;
        foreach (object record in listData) {
            int index = 0;
            object[] fieldValues = new object[dataTable.Columns.Count];
            foreach (DataColumn columnData in dataTable.Columns) {
                MemberInfo memberInfo = elementType.GetMember(columnData.ColumnName)[0];
                if (memberInfo.MemberType == MemberTypes.Property) {
                    PropertyInfo propertyInfo = memberInfo as PropertyInfo;
                    fieldValues[index] = propertyInfo.GetValue(record, null);
                } else if (memberInfo.MemberType == MemberTypes.Field) {
                    FieldInfo fieldInfo = memberInfo as FieldInfo;
                    fieldValues[index] = fieldInfo.GetValue(record);
                }
                index += 1;
            }
            dataTable.Rows.Add(fieldValues);
        }
    }
    return dataTable;
}

/// <summary>
/// Check if a type is Nullable type
/// </summary>
/// <param name="propertyType">Type to be checked</param>
/// <returns>true/false</returns>
/// <remarks></remarks>
private static bool IsNullableType(Type propertyType)
{
    return (propertyType.IsGenericType) && (object.ReferenceEquals(propertyType.GetGenericTypeDefinition(), typeof(Nullable<>)));
}

Conversion of List to DataTable

5 solutions

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Solution 1

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