将多个SqlParameter传递给方法

Question

In my main form, I have implemented this code..

void SampleMethod(string name, string lastName, string database)
{
        SqlParameter sqlParam = new SqlParameter();
        sqlParam.ParameterName = "@name";
        sqlParam.Value = name;
        sqlParam.SqlDbType = SqlDbType.NVarChar;

        SqlParameter sqlParam1 = new SqlParameter();
        sqlParam1.ParameterName = "@lastName";
        sqlParam1.Value = lastName;
        sqlParam1.SqlDbType = SqlDbType.NVarChar;

        SqlParameter sqlParam2 = new SqlParameter();
        sqlParam2.ParameterName = "@database";
        sqlParam2.Value = database;
        sqlParam2.SqlDbType = SqlDbType.NVarChar;

        SampleClass sampleClass = new SampleClass(new DBConn(@serverName, tableName, userName, password));
        sampleClass.executeStoredProc(dataGridView1, "sp_sampleStoredProc", sqlParam, sqlParam1, sqlParam2);
}

And in my SampleClass , I have this kind of method.

public DataGridView executeStoredProc(DataGridView dtgrdView, string storedProcName, params SqlParameter[] parameters)
{
        try
        {
            DataTable dt = new DataTable();
            sqlDA = new SqlDataAdapter(storedProcName, sqlconn);
            sqlDA.SelectCommand.CommandType = CommandType.StoredProcedure;
            sqlDA.SelectCommand.CommandTimeout = 60;

            // Loop through passed parameters
            if (parameters != null && parameters.Length > 0)
            {
                foreach (var p in parameters)
                    sqlDA.SelectCommand.Parameters.Add(p);
            }

            sqlDA.Fill(dt);
            dtgrdView.DataSource = dt;
            sqlconn.Close();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
            sqlconn.Close();
        }

        return dtgrdView;
}

What I am trying to do is avoid multiple

SqlParameter sqlParam = new SqlParameter() 

in my code, I have tried so many solutions for this problem but I didn't get the right answer. I have also tried to research about this but I still couldn't get the right answer.

Please don't mind my naming convention and other codes as I intentionally change many of them :) Thanks.

Answer 1

As an alternative to your solution, try to use already existing one instead, using Dapper ( https://github.com/StackExchange/dapper-dot-net ).

You still need to use multiple parameters if your stored procedure or query needs it, but this is nicely abstracted for you and this will definatelly reduce the amount of code.

void SampleMethod(string name, string lastName, string database)
{
    using(var connection = new SqlConnection(MY_CONNECTION_STRING))
    {
        var resultListOfRows = connection.Query<ReturnObject>(MY_STORED_PROCEDURE, new { 
            name = name,
            lastName = lastName,
            database = database}, commandType: System.Data.CommandType.StoredProcedure);
    }
}

Answer 2

Separate your Database logic at one place(put sqladapter, sqlcommand etc at one place), Then encapsulate parameters within your command like mentioned below and you don't need to declare sqlparameter separately, add it inside parameters list.

 cmdToExecute.Parameters.Add(new SqlParameter("@parameter", value));

Take a look at the complete example below

    public DataTable ProdTypeSelectAll(string cultureCode)
    {
        SqlCommand cmdToExecute = new SqlCommand();
        cmdToExecute.CommandText = "dbo.[pk_ProdType_SelectAll]";
        cmdToExecute.CommandType = CommandType.StoredProcedure;
        DataTable toReturn = new DataTable("ProdType");
        SqlDataAdapter adapter = new SqlDataAdapter(cmdToExecute);
        cmdToExecute.Connection = _mainConnection;
        cmdToExecute.Parameters.Add(new SqlParameter("@CultureName", cultureCode));
        _mainConnection.Open();
        adapter.Fill(toReturn);
        return toReturn;
}

Answer 3

First of all, the easiest option would be to use a microORM like Dapper, and retrieve a strongly-typed collection. Gridviews can bind to anything, including strongly typed collections. All this code could become:

using(var con=new SqlConnection(myConnectionString))
{
    con.Open();
    var result= connection.Query<ResultClass>("sp_MySproc", 
                         new { Name= name, LastName= lastName,Database=database},
                         commandType: CommandType.StoredProcedure);
    return result;
}

Even when using raw ADO.NET, you can create a SqlParameter in one line by using the appropriate constructor . For example, you can create a new nvarchar(n) parameter with:

var myParam=new SqlParameter("@name",SqlDbType.NVarchar,20);

or

var myParam=new SqlParameter("@name",SqlDbType.NVarchar,20){Value = name};

A better idea though is to create the SqlCommand object just once and reuse it. Once you have an initialized SqlCommand object, you can simply set a new connection to it and change the parameter values, eg:

public void Init()
{
    _loadCustomers = new SqlCommand(...);
    _loadCustomers.Parameters.Add("@name",SqlDbType.NVarChar,20);
    ...
}

//In another method :
using(var con=new SqlConnection(myConnectionString)
{       
    _loadCustomers.Connection=con;
    _loadCustomers.Parameters["@name"].Value = myNameParam;
    con.Open();
    using(var reader=_load.ExecuteReader())
    {
    //...
    }
}

You can do the same thing with a SqlDataAdapter, in fact that's how Windows Forms and Data Adapters are meant to be used since .NET 1.0 .

Instead of creating a new one each time you want to fill your grid, create a single one and reuse it by setting the connection and parameters before execution. You can use the SqlDataAdapter(SqlCommand) constructor to make things a bit cleaner:

public void Init()
{
    _loadCustomers = new SqlCommand(...);
    _loadCustomers.Parameters.Add("@name",SqlDbType.NVarChar,20);
    ....
    _myGridAdapter = new SqlDataAdapter(_loadCustomers);
    ...
}

And call it like this:

using(var con=new SqlConnection(myConnectionString))
{
    _myGridAdapter.SelectCommand.Connection=con;
    _myGridAdapter.SelectCommand.Parameters["@name"].Value =....;
    con.Open();

    var dt = new DataTable();
    _myGridAdapter.Fill(dt);
    dtgrdView.DataSource = dt;
    return dtgrdView;
}

Answer 4

You may be able to use the SqlParameter Constructor (String, Object) . Replace:

sampleClass.executeStoredProc(dataGridView1,
        "sp_sampleStoredProc",
        sqlParam,
        sqlParam1,
        sqlParam2);

With:

sampleClass.executeStoredProc(dataGridView1,
        "sp_sampleStoredProc",
        new SqlParameter("@name", (object)name),
        new SqlParameter("@lastName", (object)lastName),
        new SqlParameter("@database", (object)database));

However, doing this is unlikely to make your code any faster, but will reduce readability.