feat: add AddWithValue extension methods for DbParameterCollection to support base DbCommand abstraction

Author: vkuttyp

src/CosmoSQLClient.MsSql/MsSqlParameter.cs

@@ -196,3 +196,25 @@ private static DbType InferDbType(Type type)
         _ => SqlDbType.Variant
     };
 }
+
+/// <summary>
+/// Provides extension methods for <see cref="DbParameterCollection"/> to support <c>AddWithValue</c>
+/// even when the command is typed as the base <see cref="DbCommand"/>.
+/// </summary>
+public static class MsSqlParameterCollectionExtensions
+{
+    /// <summary>
+    /// Adds a parameter to the collection with the specified name and value.
+    /// </summary>
+    public static MsSqlParameter AddWithValue(this DbParameterCollection collection, string name, object? value)
+    {
+        if (collection is MsSqlParameterCollection msSqlCollection)
+        {
+            return msSqlCollection.AddWithValue(name, value);
+        }
+        
+        var p = new MsSqlParameter(name, value);
+        collection.Add(p);
+        return p;
+    }
+}

src/CosmoSQLClient.MySql/MySqlCommand.cs

@@ -71,6 +71,17 @@ public MySqlParameter AddWithValue(string name, object? value)
     internal IReadOnlyList<SqlParameter> ToCoreParameters() => _params.Select(p => p.ToCoreParameter()).ToList();
 }
 
+public static class MySqlParameterCollectionExtensions
+{
+    public static MySqlParameter AddWithValue(this DbParameterCollection collection, string name, object? value)
+    {
+        if (collection is MySqlParameterCollection mySqlCollection) return mySqlCollection.AddWithValue(name, value);
+        var p = new MySqlParameter(name, value);
+        collection.Add(p);
+        return p;
+    }
+}
+
 public sealed class MySqlDataReader : DbDataReader
 {
     private readonly IReadOnlyList<SqlRow> _rows;

src/CosmoSQLClient.Postgres/PostgresParameter.cs

@@ -111,3 +111,14 @@ private int GetIndex(string name)
 
     internal IReadOnlyList<SqlParameter> ToCoreParameters() => _params.Select(p => p.ToCoreParameter()).ToList();
 }
+
+public static class PostgresParameterCollectionExtensions
+{
+    public static PostgresParameter AddWithValue(this DbParameterCollection collection, string name, object? value)
+    {
+        if (collection is PostgresParameterCollection pgCollection) return pgCollection.AddWithValue(name, value);
+        var p = new PostgresParameter(name, value);
+        collection.Add(p);
+        return p;
+    }
+}

src/CosmoSQLClient.Sqlite/SqliteCommand.cs

@@ -71,6 +71,17 @@ public SqliteParameter AddWithValue(string name, object? value)
     internal IReadOnlyList<SqlParameter> ToCoreParameters() => _params.Select(p => p.ToCoreParameter()).ToList();
 }
 
+public static class SqliteParameterCollectionExtensions
+{
+    public static SqliteParameter AddWithValue(this DbParameterCollection collection, string name, object? value)
+    {
+        if (collection is SqliteParameterCollection sqliteCollection) return sqliteCollection.AddWithValue(name, value);
+        var p = new SqliteParameter(name, value);
+        collection.Add(p);
+        return p;
+    }
+}
+
 public sealed class SqliteDataReader : DbDataReader
 {
     private readonly IReadOnlyList<SqlRow> _rows;

tests/CosmoSQLClient.MsSql.Tests/AdoNetTests.cs

@@ -113,6 +113,24 @@ public async Task StandardAdoNet_AddWithValue_ShouldWork()
         Assert.Equal("Hello AddWithValue", result);
     }
 
+    [Fact]
+    public async Task StandardAdoNet_AddWithValue_Abstraction_ShouldWork()
+    {
+        if (ShouldSkip) return;
+
+        using DbConnection conn = new MsSqlConnection(ConnectionString);
+        await conn.OpenAsync();
+
+        using DbCommand cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT @val AS Echo";
+        
+        // This tests the EXTENSION method on the base DbParameterCollection
+        cmd.Parameters.AddWithValue("@val", "Hello Extension");
+
+        var result = await cmd.ExecuteScalarAsync();
+        Assert.Equal("Hello Extension", result);
+    }
+
     [Fact]
     public async Task StandardAdoNet_Transactions_ShouldWork()
     {