Passing a SQL parameter to an IN() clause using typed datasets in .NET

Question

First apologies as there are similar questions on this site, but none of them answer this problem directly.

Im using typed datasets in VS 2010. I create a TableAdapt

Answer 1

The only database I know of that can use parameters from .NET in an IN clause is PostgreSQL, because PostgreSQL has a concept of arrays that can be used with IN and Npgsql allows array (or IEnumerable<T>) parameters.

With other databases you have to either construct the SQL, or pass a string to a database procedure that converts it to the 0-or-more parameters and then acts on them.

Answer 2

You can also use XML to pass in a parameter list into a stored procedure:

1) In Visual Studio:

Create a new Tableadapter and create a Typed Dataset to get a single record:

SELECT * FROM myTable WHERE (ID = @ID)

2) In SQL Server Manager:

Create a stored procedure with the same select fields as your typed dataset:

CREATE PROCEDURE [dbo].[usrsp_GetIds]
    @paramList xml = NULL
AS
    SET NOCOUNT ON;

/*
Create a temp table to hold paramaters list.
Parse XML string and insert each value into table.
Param list contains: List of ID's
*/
DECLARE @tblParams AS TABLE (ID INT)
INSERT INTO @tblParams(ID) 
    SELECT 
        XmlValues.ID.value('.', 'INT')
    FROM 
        @paramList.nodes('/params/value') AS XmlValues(ID)

/* 
Select records that match ID's in param list:
*/
SELECT * FROM myTable 
WHERE 
    ID IN (
        SELECT ID FROM @tblParams
    )

3) In Visual Studio:

Add a New Query to your Tableadapter, select the stored procedure created above usrsp_GetIds and name it FillBy_Ids. This creates the command:

TableAdapter.FillBy_Ids(@paramList)

4) In Visual Studio:

In your .net code create a utility function to convert an array of strings to XML:

    ''' <summary>
    ''' Converts an array of strings to XML values.
    ''' </summary>
    ''' <remarks>Used to pass parameter values to the data store.</remarks>
    Public Shared Function ConvertToXML(xmlRootName As String, values() As String) As String
        'Note: XML values must be HTML encoded.
        Dim sb As New StringBuilder
        sb.AppendFormat("<{0}>", HttpUtility.HtmlEncode(xmlRootName))
        For Each value As String In values
            sb.AppendLine()
            sb.Append(vbTab)
            sb.AppendFormat("<value>{0}</value>", HttpUtility.HtmlEncode(value))
        Next
        sb.AppendLine()
        sb.AppendFormat("</{0}>", xmlRootName)
        Return sb.ToString
    End Function

Usage Example:

Fill your data table using the strongly typed functions by passing a list of strings as a parameter:

'Create a list of record IDs to retrieve:
Dim ids as New List(of String)
ids.Add(1)
ids.Add(2)
ids.Add(3)

'Convert the list of IDs to an XML string:
Dim paramsXml As String = ConvertToXML("params", ids.ToArray)

'Get the records using standard DataTable & TableAdapter methods:
Using myDT As New MyDataTable
    Using myTA As New MyTableAdapter

        myTA.FillBy_Ids(myDT, paramsXml)

        For Each row In myDT
            'do stuff:
        Next

    End Using
End Using