问题
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 TableAdapter in a Dataset with a query like:
SELECT * from Table WHERE ID IN(@IDs)
Now if I call: TableAdapter.Fill(MyDataTable,"1,2,3") an error occurs stating that VS cannot convert 1,2,3 to type int. Fair enough.
So then i decide to change the Parameter (i.e. @IDs) type to string in the Parameter collection. Try again - still the same error message.
So is there any way this typed dataset can accept my "1,2,3" parameter? At the moment i only have a few parameters to pass, so i could easily just create 5 or so parameters and pass them separately, but what if there are hundreds? Is there any way I can call the Fill() method with my comma separated parameter?
(i know i can use Dynamic SQL to create the statement and execute it but would prefer if there is another way allowing me to keep my typed dataset for use in e.g. ReportViewer/bindingsources)
回答1:
You can't use a single parameter for a list of values in this way. But there may be database-specific ways to achieve what you want. For example, with SQL Server 2005 or later you could create a table-valued function to split your string parameter, something like:
CREATE FUNCTION dbo.F_Split
(
@InputString VARCHAR(MAX)
,@Separator VARCHAR(MAX)
)
RETURNS @ValueTable TABLE (Value VARCHAR(MAX))
AS
BEGIN
DECLARE @SeparatorIndex INT, @TotalLength INT, @StartIndex INT, @Value VARCHAR(MAX)
SET @TotalLength=LEN(@InputString)
SET @StartIndex = 1
IF @Separator IS NULL RETURN
WHILE @StartIndex <= @TotalLength
BEGIN
SET @SeparatorIndex = CHARINDEX(@Separator, @InputString, @StartIndex)
IF @SeparatorIndex > 0
BEGIN
SET @Value = SUBSTRING(@InputString, @StartIndex, @SeparatorIndex-@StartIndex)
SET @StartIndex = @SeparatorIndex + 1
END
ELSE
BEGIN
Set @Value = SUBSTRING(@InputString, @StartIndex, @TotalLength-@StartIndex+1)
SET @StartIndex = @TotalLength+1
END
INSERT INTO @ValueTable
(Value)
VALUES
(@Value)
END
RETURN
END
You would then use it as follows:
SELECT * from Table WHERE ID IN (SELECT CAST(Value AS INT) FROM F_Split(@IDs, ','))
回答2:
I tried a workaround for using string "contains" concept in SQL way:
In your case, change the SQL -
Original:
SELECT * from Table WHERE ID IN(@IDs)
Become:
SELECT * from Table WHERE CharIndex(','+Cast(ID As Varchar(10))+',',@IDs) > 0
With .net code -
Original:
TableAdapter.Fill(MyDataTable,"1,2,3")
Become:
TableAdapter.Fill(MyDataTable,",1,2,3,")
回答3:
SQL Server 2008 has a feature called Table-Valued Parameters
So you need to
- define your query as
SELECT * from Table WHERE ID IN (SELECT * FROM (@IDs)) - go back in the TableAdapter visual designer in Visual Studio, and update the @IDS parameter to modify the @IDS parameter as DbType=Object and ProviderType=Structured
- run this SQL batch in the database your are using:
CREATE TYPE MyIntArray AS TABLE ( Value INT );GO. This will create a MyIntArray "table type" with just one column of INT type. - Now the tricky thing is to pass the "MyIntArray" type to the TableAdapter, on the ADO.NET side.
Unfortunately the Table Adapter designer does not support the SqlParameter.TypeName argument, so we need to fix it by ourselves. The goal is to modify the CommandCollection property of the generated TableAdapter class. Unfortunately, this property is protected, so you have to derive the TableAdapter or for example use Reflection to tweak it. Here is an example with a derived class:
public class MyTableAdapter2 : MyTableAdapter
{
public MyTableAdapter2()
{
SqlCommand[] cmds = base.CommandCollection;
// here, the IDS parameter is index 0 of command 1
// you'll have to be more clever, but you get the idea
cmds[1].Parameters[0].TypeName = "MyIntArray";
}
}
And this is how you can call this method:
MyTableAdapter t = new MyTableAdapter2();
// create the TVP parameter, with one column. the name is irrelevant.
DataTable tvp = new DataTable();
tvp.Columns.Add();
// add one row for each value
DataRow row = tvp.NewRow();
row[0] = 1;
tvp.Rows.Add(row);
row = tvp.NewRow();
row[0] = 2;
tvp.Rows.Add(row);
row = tvp.NewRow();
row[0] = 3;
tvp.Rows.Add(row);
t.Fill(new MyDataTable(), tvp);
回答4:
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.
回答5:
@Joe is right.
Or you can use foreach loop to do that.
Something like:
int[] arr = new int[3];
arr[0] = "1";
arr[1] = "2";
arr[2] = "3";
foreach(vat data in arr)
{
//Do your Code here
//
var MyDatatable = obj.GetDatabyID(data);
TableAdapter.Fill(MyDataTable);
}
Regards
回答6:
You also can create a list of IDs parameters so instead of using @IDs you will use @ID1, @ID2, @ID3, etc
var sql = "SELECT * from Table WHERE ID IN (" + getKeys(values.Count) + ")";
And getKeys(count) do something like this:
var result = string.Empty;
for (int i = 0; i < count; i++)
{
result += ", @ID" + i;
}
return string.IsNullOrEmpty(result) ? string.Empty : result.Substring(1);
and Finally, add the parameters:
foreach (int i = 0; i < values.Count; i++)
{
cmd.Parameters.Add(new SqlParameter("@ID" + i, SqlDbType.VarChar) { Value = values[i]});
}
回答7:
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
回答8:
I was able to solve this by setting the ClearBeforeFill property to to false and filling the TableAdapter in a foreach loop.
List<string> aList = new List<string>();
aList.Add("1");
aList.Add("2");
aList.Add("3");
yourTableAdapter.ClearBeforeFill = true;
yourTableAdapter.Fill(yourDataSet.yourTableName, ""); //clears table
foreach (string a in aList)
{
yourTableAdapter.ClearBeforeFill = false;
yourTableAdapter.Fill(yourDataSet.yourTableName, a);
}
yourTableAdapter.Dispose();
来源：https://stackoverflow.com/questions/5401641/passing-a-sql-parameter-to-an-in-clause-using-typed-datasets-in-net