I'm encountering an issue when using the Npgsql library in my .NET Framework 4.6.1 project. Specifically, I'm getting the following exception when attempting to open an NpgsqlConnection:
Method 'DisposeAsync' in type 'Npgsql.NpgsqlBinaryExporter' from assembly 'Npgsql, Version=4.1.14.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7' does not have an implementation.
Code Reference:
The error occurs at the point where I open the connection:
public static DataTable FetchMasterData()
{
NpgsqlConnection npgsqlConn = new NpgsqlConnection(Connection.ConnectionStringPostgreSQL);
DataTable classMasterTbl = new DataTable();
string sqlQuery = string.Empty;
NpgsqlCommand npgsqlCommand = null;
try
{
sqlQuery = @"SELECT * FROM ClassMaster";
npgsqlCommand = new NpgsqlCommand(sqlQuery, npgsqlConn);
npgsqlConn.Open(); // Getting Error here
NpgsqlDataAdapter dataAdapter = new NpgsqlDataAdapter(npgsqlCommand);
dataAdapter.Fill(classMasterTbl);
return classMasterTbl;
}
catch (Exception dalExce)
{
// Handled LoaderExceptions
}
finally
{
npgsqlCommand?.Dispose();
npgsqlConn.Close();
}
}
.csProj
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<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProductVersion>8.0.30703</ProductVersion>
<SchemaVersion>2.0</SchemaVersion>
<ProjectGuid>{DD58513D-7209-4DEF-A9EA-9C751367A14E}</ProjectGuid>
<OutputType>Library</OutputType>
<AppDesignerFolder>Properties</AppDesignerFolder>
<RootNamespace>DAL</RootNamespace>
<AssemblyName>DAL</AssemblyName>
<TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
<FileAlignment>512</FileAlignment>
<TargetFrameworkProfile />
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
<DebugSymbols>true</DebugSymbols>
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<OutputPath>bin\Debug\</OutputPath>
<DefineConstants>DEBUG;TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
<PlatformTarget>AnyCPU</PlatformTarget>
<Prefer32Bit>false</Prefer32Bit>
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<DebugType>pdbonly</DebugType>
<Optimize>true</Optimize>
<OutputPath>bin\Release\</OutputPath>
<DefineConstants>TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
<Prefer32Bit>false</Prefer32Bit>
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<PropertyGroup>
<StartupObject />
</PropertyGroup>
<PropertyGroup>
<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
</PropertyGroup>
<ItemGroup>
<Reference Include="Microsoft.Bcl.AsyncInterfaces, Version=1.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\Microsoft.Bcl.AsyncInterfaces.1.1.0\lib\net461\Microsoft.Bcl.AsyncInterfaces.dll</HintPath>
</Reference>
<Reference Include="Npgsql, Version=4.1.14.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7, processorArchitecture=MSIL">
<HintPath>..\packages\Npgsql.4.1.14\lib\net461\Npgsql.dll</HintPath>
</Reference>
<Reference Include="System" />
<Reference Include="System.Buffers, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\System.Buffers.4.5.0\lib\netstandard2.0\System.Buffers.dll</HintPath>
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<Reference Include="System.configuration" />
<Reference Include="System.Core" />
<Reference Include="System.Data.Linq" />
<Reference Include="System.Memory, Version=4.0.1.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\System.Memory.4.5.3\lib\netstandard2.0\System.Memory.dll</HintPath>
</Reference>
<Reference Include="System.Numerics" />
<Reference Include="System.Runtime.CompilerServices.Unsafe, Version=4.0.5.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
<HintPath>..\packages\System.Runtime.CompilerServices.Unsafe.4.6.0\lib\netstandard2.0\System.Runtime.CompilerServices.Unsafe.dll</HintPath>
</Reference>
<Reference Include="System.Numerics.Vectors, Version=4.1.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
<HintPath>..\packages\System.Numerics.Vectors.4.4.0\lib\net46\System.Numerics.Vectors.dll</HintPath>
</Reference>
<Reference Include="System.Text.Encodings.Web, Version=4.0.4.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\System.Text.Encodings.Web.4.6.0\lib\netstandard2.0\System.Text.Encodings.Web.dll</HintPath>
</Reference>
<Reference Include="System.Text.Json, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\System.Text.Json.4.6.0\lib\net461\System.Text.Json.dll</HintPath>
</Reference>
<Reference Include="System.Threading.Tasks.Extensions, Version=4.2.0.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\System.Threading.Tasks.Extensions.4.5.4\lib\net461\System.Threading.Tasks.Extensions.dll</HintPath>
</Reference>
<Reference Include="System.ValueTuple, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>..\packages\System.ValueTuple.4.5.0\lib\net461\System.ValueTuple.dll</HintPath>
</Reference>
<Reference Include="System.Xml.Linq" />
<Reference Include="System.Data.DataSetExtensions" />
<Reference Include="Microsoft.CSharp" />
<Reference Include="System.Data" />
<Reference Include="System.Xml" />
</ItemGroup>
<ItemGroup>
<None Include="app.config" />
<None Include="packages.config" />
<None Include="Properties\Settings.settings">
<Generator>SettingsSingleFileGenerator</Generator>
<LastGenOutput>Settings.Designer.cs</LastGenOutput>
</None>
</ItemGroup>
<ItemGroup>
<Service Include="{3259AA49-8AA1-44D3-9025-A0B520596A8C}" />
</ItemGroup>
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
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Other similar extension points exist, see Microsoft.Common.targets.
<Target Name="BeforeBuild">
</Target>
<Target Name="AfterBuild">
</Target> -->
</Project>
Target Framework: .NET Framework 4.6.1
Npgsql Version: 4.1.14.0
Database: PostgreSQL
Research:
From what I've gathered, the DisposeAsync method is part of the asynchronous disposal pattern introduced in .NET Core 3.0. However, since I’m using .NET Framework 4.6.1, this method is not natively supported. This seems to be causing the runtime exception.
Questions:
Any guidance or suggestions would be greatly appreciated!
After downgrading Npgsql to 4.0.17.0, I was able to resolve this issue.