I have a datatable like this:

I want to convert it to a dictionary where the first column is the key. The combination of the second column with lowercase letters and the third column is the value.

Expected result:

This is my code:

DataTable dt = new DataTable();
dt.Columns.Add("Column1");
dt.Columns.Add("Column2");
dt.Columns.Add("Column3");

dt.Rows.Add("Name1", "Code111", 12550);
dt.Rows.Add("Name2", "Code112", 12551);
dt.Rows.Add("Name3", "Code113", 12553);
dt.Rows.Add("Name4", "Code114", 12554);

Dictionary<string,string> dic = new Dictionary<string,string>();

for (int i = 0; i < dt.Rows.Count; i  )
{
    string _k = dt.Rows[i][0].ToString();
    string _v = dt.Rows[i][1].ToString().ToLower()  "_"  
    dt.Rows[i][2].ToString();

    dic.Add(_k, _v);
}

Is there a better way to convert a datatable to a dictionary? For example, can I use Linq?

CodePudding user response：

You can use the linq.enumerable.todictionary to convert the DataTable into a Dictionary:

var _dic = dt.AsEnumerable()
                   .ToDictionary<DataRow, string, string>(row => row.Field<string>(0),
                   row => row.Field<string>(1).ToLower()   "_"   row.Field<string>(2) );

CodePudding user response：

Since .NET 6 is the oldest supported .NET Core version, one can use ranges to reduce the code to this :

var dict=dt.AsEnumerable().ToDictionary(
    r=>r[0],
    r=>String.Join('_',r.ItemArray[1..]));

If the values need to be lowercase, ToLower() can be called after joining.

var dict=dt.AsEnumerable().ToDictionary(
    r=>r[0],
    r=>String.Join('_',r.ItemArray[1..])?.ToLower());