How to Extract Unique Rows from a DataTable into a String Array in .NET?

Extracting Distinct Rows into an Array Using DataView

When working with datasets, it's often necessary to extract distinct rows based on specific criteria. This knowledge base article will guide you through the steps to select distinct rows from a DataTable and store them into an array.

Context:

You have a dataset (objds) containing a table named Table1. Table1 includes a column called ProcessName with potential duplicate values. Your objective is to retrieve only the unique names from this column.

Solution:

To accomplish this, you need to leverage the DataView class in .NET. Follow these steps:

1. Create a DataView instance using the Table1 DataTable:

   DataView view = new DataView(table);

2. Use the ToTable method to generate a DataTable containing only the distinct rows:

   DataTable distinctValues = view.ToTable(true, "ProcessName" /*, other column names... */);

3. Store the unique names from the distinctValues DataTable into an array:

   string[] intUniqId = new string[distinctValues.Rows.Count];
   for (int i = 0; i < intUniqId.Length; i++)
   {
       intUniqId[i] = distinctValues.Rows[i]["ProcessName"].ToString();
   }

By implementing these steps, you can successfully extract and store distinct rows into an array for further processing or display in your application.

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