How to work with dataTable?

Question

My given problem is follow:

I have an object with x coloums and every coloum has y values. I must now bring this to excel.

I found an snippet in which a datatable can be exported easily.

So I will bring my object to a datatable. How can I do this?

Language is C#.´Net

Answer 1

You can use reflection to get the fields of the object and add the columns to the DataTable:

private bool IsNullableType(Type theType)
{
    return (theType.IsGenericType && theType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)));
}


// Create the columns based on the data in the album info - get by reflection
var ai = new <your object without data>;
Type t = ai.GetType();

this.dataTable.TableName = t.Name;

foreach (PropertyInfo p in t.GetProperties())
{
    var columnSpec = new DataColumn();
    // If nullable get the underlying type
    Type propertyType = p.PropertyType;
    if (IsNullableType(propertyType))
    {
        var nc = new NullableConverter(propertyType);
        propertyType = nc.UnderlyingType;
    }
    columnSpec.DataType = propertyType;
    columnSpec.ColumnName = p.Name;
    this.dataTable.Columns.Add(columnSpec);
}

this.dataGridView.DataSource = dataTable;

Then to add a row to the table:

var info = new <your object with data>;
// Add by reflection
Type t = info.GetType();
var row = new object[t.GetProperties().Length];

int index = 0;
foreach (PropertyInfo p in t.GetProperties())
{
    row[index++] = p.GetValue(info, null);
}

this.dataTable.Rows.Add(row);

Answer 2

I'm not completely certain I know what you're trying to do. I assume you want to create a DataTable and load your existing object into it. Assuming your class looks something like this:

public class MyClass {
    public int ID {get;set;}
    public string Column1 {get;set;}
    public DateTime Column2 {get;set;}
    // ...
}

and assuming you have a list of them you want to copy into a DataTable, here's how:

DataTable dt = new DataTable("MyTable");
dt.Columns.Add("ID", typeof(int));
dt.Columns.Add("Column1", typeof(string));
dt.Columns.Add("Column2", typeof(DateTime));

foreach (var o in _myObjectList) {
    DataRow dr = dt.NewRow();
    dr["ID"] = o.ID;
    dr["Column1"] = o.Column1;
    dr["Column2"] = o.Column2;
    dt.Rows.Add(dr);
}