DapperLib/Dapper

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Dapper - a simple object mapper for .Net

Stars: 18.4k
Forks: 3.7k
Open beginner issues: 0
Indexed issues: 466
Avg merge: 5h 8m
Merged PRs (30d): 1

Dominant language: C#
License: No license data
Last GitHub push: Sep 12, 2026
Latest indexed: Sep 20, 2026
Contributing guide: No contributing guide
Code of conduct: No code of conduct
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466 issues indexed so far

SQL Server sql_variant mapping regression in 2.1.86: SERVERPROPERTY Int32 to bool throws InvalidCastException Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 68/100

DapperLib/Dapper#2234 · Opened Sep 17, 2026
Dapper.AOT leaves trim-unsafe Dapper reflection paths reachable during Native AOT publish Open

Difficulty 4/5 3-5 days Newbie friendliness 52/100

DapperLib/Dapper#2232 · 1 comment · Opened Sep 14, 2026
PostgreSQL SMALLINT[] mapping fails in Dapper 2.1.86 but works in 2.1.79 Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 72/100

DapperLib/Dapper#2231 · 2 reactions · Opened Sep 13, 2026
Query<DateOnly> / Query<TimeOnly> (scalar form) silently return default(T) Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

DapperLib/Dapper#2227 · Opened Aug 20, 2026
DateOnly/DateTime coercion gaps on 'date' columns (breaks with Npgsql 10, and SqlClient the other way) Open

Difficulty 3/5 1-2 days Newbie friendliness 67/100

DapperLib/Dapper#2226 · Opened Aug 20, 2026
cmd.Cancel() in QueryRowImpl finally block causes ORA-1013 on Oracle Database Queries Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

DapperLib/Dapper#2215 · 2 comments · Opened Jun 19, 2026
Proposal: Built-in extensibility for structured logging (commands, parameters, connections, transactions) Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2201 · 3 comments · Opened Mar 30, 2026
No QueryAsync overload which accepts CommandDefinition, for cancellation, and Type array, for unbounded map Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

DapperLib/Dapper#2193 · 1 comment · Opened Feb 22, 2026
Feature Request: Support for Open Generic TypeHandler registration Open

Difficulty 5/5 Over a week Newbie friendliness 45/100

DapperLib/Dapper#2190 · 1 comment · Opened Feb 4, 2026
QueryUnbufferedAsync cancels command unnecessarily for Npgsql, causing performance degradation Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

DapperLib/Dapper#2188 · 1 comment · Opened Jan 16, 2026
Nullable input parameter not supplied when NULL Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 38/100

DapperLib/Dapper#2187 · 3 comments · Opened Jan 8, 2026
Command not disposed with async using and ExecuteReaderAsync Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 50/100

DapperLib/Dapper#2185 · 1 comment · Opened Nov 13, 2025
[Question]: Unused value in the QueryAsync<T> Open

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

DapperLib/Dapper#2184 · 4 comments · Opened Oct 30, 2025
Literal replacements causing DAP214 Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 48/100

DapperLib/Dapper#2181 · 1 comment · Opened Sep 28, 2025
Possible bug: `GridReader` constructor uses `DynamicParameters` cast instead of `IParameterCallbacks` Open

bug needs-triage

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

DapperLib/Dapper#2179 · 1 comment · Opened Aug 22, 2025
Improve AI documentation to include Logging preferences Open

Difficulty 2/5 1-3 hours Newbie friendliness 38/100

DapperLib/Dapper#2176 · 1 comment · Opened Jul 24, 2025
Cache purge tweaking Open

Difficulty 5/5 Over a week Newbie friendliness 28/100

DapperLib/Dapper#2173 · 7 comments · Opened Jun 13, 2025
Dapper TVP Behavior and SQL Server Monitoring Overhead Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

DapperLib/Dapper#2170 · 2 comments · Opened Jun 3, 2025
All nuget packages to consist of strong named dll Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

DapperLib/Dapper#2169 · 9 comments · Opened May 30, 2025
[Optimization] Proposal: Span-based mapping for reduced allocations Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2166 · 5 comments · Opened May 13, 2025
Using custom Dapper ITypeHandler for parsing data but cause conflict to handle SQL parameters Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 35/100

DapperLib/Dapper#2165 · Opened May 12, 2025
Proposal: Custom Deserializer Methods Open

DapperLib/Dapper#2164 · 3 comments · 1 assignee · Opened May 1, 2025
Does't support SQLite at Linux ARM64 Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 30/100

DapperLib/Dapper#2162 · 4 comments · Opened Apr 28, 2025
Proposal: add support for ILogger (Microsoft.Extensions.Logging) Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2161 · 1 comment · 2 reactions · Opened Apr 28, 2025
QueryAsync sometimes returns data for a different request than the current one Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 30/100

DapperLib/Dapper#2159 · 5 comments · Opened Apr 19, 2025
net461 has reached EOL. Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 35/100

DapperLib/Dapper#2158 · 6 comments · Opened Apr 17, 2025
DynamicParameters DbType Mapping Issues in Parameterized Queries Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2157 · Opened Apr 11, 2025
SplitOn column is needed twice in the query to work properly Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 38/100

DapperLib/Dapper#2155 · Opened Mar 30, 2025
Feature Request: Add SplitAfter parameter as alternative to SplitOn Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

DapperLib/Dapper#2154 · Opened Mar 18, 2025
DIPSAS Dapper.Oracle is Deprecated - migration path? Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

DapperLib/Dapper#2152 · 2 comments · Opened Mar 13, 2025
Dapper currently has hardcoded values for cache eviction: Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2151 · 1 comment · Opened Mar 3, 2025
parameter in tablename Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

DapperLib/Dapper#2150 · Opened Feb 19, 2025
Dapper works for a while, then can't find constructor Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 25/100

DapperLib/Dapper#2142 · 10 comments · 1 reaction · Opened Jan 21, 2025
Parameter size overwritten after custom TypeHandler Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 48/100

DapperLib/Dapper#2141 · Opened Jan 7, 2025
API Proposal - example code included Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2137 · 1 comment · Opened Dec 20, 2024
API proposal: custom interpolated string handler Open

area:sqlbuilder feature request proposal

DapperLib/Dapper#2136 · 20 comments · 22 reactions · 1 assignee · Opened Dec 14, 2024
DynamicParameters retrieval failing with NullReferenceException after moving to Microsoft.Data.SqlClient Open

bug needs-triage

Difficulty 4/5 3-5 days Newbie friendliness 30/100

DapperLib/Dapper#2135 · Opened Dec 10, 2024
Firebird: Insert with blob.Length > 4000 fails with System.ArgumentOutOfRangeException Open

bug needs-triage

Difficulty 3/5 1-2 days Newbie friendliness 35/100

DapperLib/Dapper#2134 · 2 comments · Opened Dec 7, 2024
Allow custom Command creation Open

Difficulty 2/5 1-3 hours Newbie friendliness 52/100

DapperLib/Dapper#2127 · Opened Oct 31, 2024
QueryAsync with custom mapping AND CancellationToken Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

DapperLib/Dapper#2125 · 7 comments · Opened Oct 22, 2024
InvalidProgramException: "Common Language Runtime detected an invalid program. (Dapper version:1.60.6) Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

DapperLib/Dapper#2124 · 15 comments · Opened Oct 16, 2024
Possible concurrency issues with caches? Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

DapperLib/Dapper#2117 · 9 comments · Opened Oct 2, 2024
OracleParameters implements IDisposable... What should I do. Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

DapperLib/Dapper#2114 · Opened Sep 23, 2024
MariaDB support? Open

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

DapperLib/Dapper#2111 · 3 comments · Opened Sep 16, 2024
ulong support please :) For MSSQL Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

DapperLib/Dapper#2110 · 5 comments · Opened Sep 9, 2024
Error: System.Data.DataException: Error parsing column 15 (QUANTITY=<null>) Open

Difficulty 4/5 3-5 days Newbie friendliness 28/100

DapperLib/Dapper#2109 · Opened Aug 23, 2024
Mapping to tuple hides type incompatibilities Open

Difficulty 3/5 1-2 days Newbie friendliness 52/100

DapperLib/Dapper#2108 · 2 reactions · Opened Aug 16, 2024
Column parsing error on a coalesced integer value in a view where the coalesce values are from different tables. Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

DapperLib/Dapper#2106 · 2 comments · Opened Jul 29, 2024
Throw InvalidCastException with " ORDER BY DESC\ASC " when SqlMapper CONVERT a char-type-db-column TO a string-type-c#-property Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

DapperLib/Dapper#2105 · Opened Jul 29, 2024
Create table lever mapper, rather than just column level mapping Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

DapperLib/Dapper#2104 · Opened Jul 25, 2024

DapperLib/Dapper

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