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How do you query Stored Procedure Parameters via ADO.net?

Posted on 2009-05-12
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Last Modified: 2013-12-25
I am wondering how to figure out if a store procedure has a certain parameter without a try catch. Basically we have a standard in our database where all of our stored procedures are Delete_<TableName> and a set number of parameters. Well we want to add a @ReturnValue to some but not all right away. Since it is a return value I have to add it to the stored proc because you can't make it optional. So I was wondering if there was a way to check the stored proc to see if @ReturnValue has been defined.

Is that possible?
Dim nCmd As New SqlClient.SqlCommand("Delete_" & TableName)

nCmd.CommandType = CommandType.StoredProcedure

nCmd.Parameters.AddWithValue("@Param1", val1)

nCmd.Parameters.AddWithValue("@Param2", val2)

nCmd.Parameters.AddWithValue("@Param3", val3)
 

'Need logic to check to see if @ReturnValue is on Delete_<TableName>

nCmd.Parameters.Add("@ReturnValue", SqlDbType.VarChar)

nCmd.Parameters("@ReturnValue").Direction = ParameterDirection.Output

nCmd.Parameters("@ReturnValue").Size = 250

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Question by:jmarbutt
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3 Comments
 
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Accepted Solution

by:
jmarbutt earned 0 total points
ID: 24365731
I found the answer via the SQLCommandBuilder

See this article:
http://www.davidhayden.com/blog/dave/archive/2006/11/01/SqlCommandBuilderDeriveParameters.aspx
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LVL 3

Expert Comment

by:GregTSmith
ID: 24365947
All stored procedures have an implicit return value of zero if you do not set it explicitly.  

I'll attach some of the code I was playing with because you might find it useful.

using System;

using System.Data;

using System.Data.SqlClient;
 

public class Database

{

  protected virtual string ConnectionString { get; set; }
 

  public Database(string connectionString)

  {

    this.ConnectionString = connectionString;

  }
 

  public virtual int DeleteTable(string tableName, params object[] parameters)

  {

    int returnValue = 0;
 

    this.UseCommand(

      (command) =>

      {

        command.CommandText = "Delete_" + tableName;

        command.CommandType = CommandType.StoredProcedure;
 

        SqlCommandBuilder.DeriveParameters(command);
 

        for (int i = 0; i < parameters.Length; i++)

          command.Parameters[i].Value = parameters[i];
 

        command.ExecuteNonQuery();
 

        returnValue = (int)command.Parameters[0].Value;

      }

    );
 

    return returnValue;

  }
 

  protected virtual void UseCommand(Action<SqlCommand> lambda)

  {

    this.UseConnection(

      (connection) =>

      {

        using (SqlCommand command = new SqlCommand())

        {

          command.Connection = connection;

          lambda(command);

        }

      }

    );

  }
 

  protected virtual void UseConnection(Action<SqlConnection> lambda)

  {

    using (SqlConnection connection = new SqlConnection(this.ConnectionString))

    {

      connection.Open();

      lambda(connection);

      connection.Close();

    }

  }

}

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Expert Comment

by:GregTSmith
ID: 24365969
Oops... that code won't quite work... since all procedures have a return value, you'd have to offset the parameter value you're setting by 1...  ignore the last code posting and look at this one instead.
using System;

using System.Data;

using System.Data.SqlClient;
 

public class Database

{

  protected virtual string ConnectionString { get; set; }
 

  public Database(string connectionString)

  {

    this.ConnectionString = connectionString;

  }
 

  public virtual int DeleteTable(string tableName, params object[] parameters)

  {

    int returnValue = 0;
 

    this.UseCommand(

      (command) =>

      {

        command.CommandText = "Delete_" + tableName;

        command.CommandType = CommandType.StoredProcedure;
 

        SqlCommandBuilder.DeriveParameters(command);
 

        for (int i = 0; i < parameters.Length; i++)

          command.Parameters[i + 1].Value = parameters[i];
 

        command.ExecuteNonQuery();
 

        returnValue = (int)command.Parameters[0].Value;

      }

    );
 

    return returnValue;

  }
 

  protected virtual void UseCommand(Action<SqlCommand> lambda)

  {

    this.UseConnection(

      (connection) =>

      {

        using (SqlCommand command = new SqlCommand())

        {

          command.Connection = connection;

          lambda(command);

        }

      }

    );

  }
 

  protected virtual void UseConnection(Action<SqlConnection> lambda)

  {

    using (SqlConnection connection = new SqlConnection(this.ConnectionString))

    {

      connection.Open();

      lambda(connection);

      connection.Close();

    }

  }

}

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