how replace blank in place of zero for particular column in asp.net

try this

private void dtChangeZeroToNull (DataTable dataTable){
    List dcNames = dataTable.Columns
                            .Cast()
                            .Select(x => x.ColumnName)
                            .ToList(); //This querying of the Column Names, you could do with LINQ
    foreach (DataRow row in dataTable.Rows) //This is the part where you update the cell one by one
        foreach (string columnName in dcNames)
            row[columnName] = (int)row[columnName] == 0 ? DBNull.Value : row[columnName];               
}

     Where I have to change For Particular Column

  dt = (dt.AsEnumerable().Select(delegate (DataRow r)
        {

            DataRow nr = dt.NewRow();

            foreach (DataColumn item in dt.Columns)

            { 
                nr.SetField(item.ColumnName, r[item.ColumnName].ToString() == "0" ? null : r[item.ColumnName]);

            }

            return nr;

        })).CopyToDataTable();

Replace Empty with Zero (0)

string.IsNullOrEmpty(Convert.ToString(row[columnName])) ? "0" : row[columnName];