From 69fdb55f0644ff0495b1e1606e23b76b2ddfeb1b Mon Sep 17 00:00:00 2001
From: sunkaixuan <610262374@qq.com>
Date: Sun, 27 Mar 2022 21:40:04 +0800
Subject: [PATCH] Add Queryable.ForEachByPage

---
 .../QueryableProvider/QueryableProvider.cs    | 38 +++++++++++++++++++
 Src/Asp.Net/SqlSugar/Interface/IQueryable.cs  |  2 +-
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/Src/Asp.Net/SqlSugar/Abstract/QueryableProvider/QueryableProvider.cs b/Src/Asp.Net/SqlSugar/Abstract/QueryableProvider/QueryableProvider.cs
index d0f29ff2c..4d08a8053 100644
--- a/Src/Asp.Net/SqlSugar/Abstract/QueryableProvider/QueryableProvider.cs
+++ b/Src/Asp.Net/SqlSugar/Abstract/QueryableProvider/QueryableProvider.cs
@@ -1293,6 +1293,44 @@ namespace SqlSugar
                 }
             }
         }
+        public virtual void ForEachByPage(Action<T> action, int pageIndex, int pageSize, ref int totalNumber, int singleMaxReads = 300, System.Threading.CancellationTokenSource cancellationTokenSource = null)
+        {
+            int count = this.Clone().Count();
+            if (count > 0)
+            {
+                if (pageSize > singleMaxReads && count - ((pageIndex - 1) * pageSize) > singleMaxReads)
+                {
+                    Int32 Skip = (pageIndex - 1) * pageSize;
+                    Int32 NowCount = count - Skip;
+                    Int32 number = 0;
+                    if (NowCount > pageSize) NowCount = pageSize;
+                    while (NowCount > 0)
+                    {
+                        if (cancellationTokenSource?.IsCancellationRequested == true) return;
+                        if (number + singleMaxReads > pageSize) singleMaxReads = NowCount;
+                        foreach (var item in this.Clone().Skip(Skip).Take(singleMaxReads).ToList())
+                        {
+                            if (cancellationTokenSource?.IsCancellationRequested == true) return;
+                            action.Invoke(item);
+                        }
+                        NowCount -= singleMaxReads;
+                        Skip += singleMaxReads;
+                        number += singleMaxReads;
+                    }
+                }
+                else
+                {
+                    if (cancellationTokenSource?.IsCancellationRequested == true) return;
+                    foreach (var item in this.Clone().ToPageList(pageIndex, pageSize))
+                    {
+                        if (cancellationTokenSource?.IsCancellationRequested == true) return;
+                        action.Invoke(item);
+                    }
+                }
+            }
+            totalNumber = count;
+        }
+
         public List<T> ToOffsetPage(int pageIndex, int pageSize) 
         {
             if (this.Context.CurrentConnectionConfig.DbType != DbType.SqlServer)
diff --git a/Src/Asp.Net/SqlSugar/Interface/IQueryable.cs b/Src/Asp.Net/SqlSugar/Interface/IQueryable.cs
index 3a0c56df6..42495d22b 100644
--- a/Src/Asp.Net/SqlSugar/Interface/IQueryable.cs
+++ b/Src/Asp.Net/SqlSugar/Interface/IQueryable.cs
@@ -109,7 +109,7 @@ namespace SqlSugar
         ISugarQueryable<T> Select(string select);
         ISugarQueryable<T> MergeTable();
         void ForEach(Action<T> action, int singleMaxReads = 300, System.Threading.CancellationTokenSource cancellationTokenSource = null);
-
+        void ForEachByPage(Action<T> action, int pageIndex, int pageSize, ref int totalNumber, int singleMaxReads = 300, System.Threading.CancellationTokenSource cancellationTokenSource = null);
         int Count();
         Task<int> CountAsync();
         int Count(Expression<Func<T, bool>> expression);