How to change type datatable column

Question

Possible Duplicate:
How To Convert The DataTable Column type?

How can we change the datatable column type if table already have value?

Answer 1

Changing data type of datatable after get filled is not possible but one of the work abound for this is clone datatable and change type

First way

//clone datatable     
DataTable dtCloned = dt.Clone();
//change data type of column
dtCloned.Columns[0].DataType = typeof(Int32);
//import row to cloned datatable
foreach (DataRow row in dt.Rows) 
{
    dtCloned.ImportRow(row);
}

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second way

and other way to do it is like this , fill schema first - than change column datatype and than fill datable

adapter.FillSchema(table, SchemaType.Source);
table.Columns[0].DataType = typeof (Int32);
adapter.Fill(table);

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third way

one more way to do it is

System.Data.DataTable dt = new System.Data.DataTable();
dt.Columns.Add("Col1", typeof(int));
dt.Rows.Add(1);

System.Data.DataTable dt2 = new System.Data.DataTable();
dt2.Columns.Add("Col1", typeof(string));
dt2.Load(dt.CreateDataReader(), System.Data.LoadOption.OverwriteChanges);