C# 一点点

字符串："abcbeee"，要求结果如下"

a:1

b:2

c:1

e:3

 string str1 = "abcbeee"; 

            //1    hashtable
            Hashtable ht = new Hashtable(); 
            for (int i1 = 0; i1 < str1.Length; i1++)
            {
                string v = str1[i1].ToString();
                if (ht.Contains(v))
                {
                    ht[v] = int.Parse(ht[v].ToString()) + 1;
                }
                else
                {
                    ht.Add(v, 1);
                }
            } 

            char[] arr = str1.ToCharArray();  

            //2    dictionary<>
            Dictionary<string, int> dict = new Dictionary<string, int>();
            foreach (char c in arr)
            {
                if (dict.ContainsKey(c.ToString())) dict[c.ToString()]++;
                else dict.Add(c.ToString(), 1);
            }

            // 3   linq
            var q = from x in arr group x by x into Y select new { Y.Key, ct = Y.Count() };

            //4    linq
            var lis = str1.GroupBy(s => s).Select(g => new { g.Key, Count = g.Count() });

输出数组内容

        string[] names = {"wang","zhang","liu","zhao","li" };

        Console.WriteLine("\n1 by method");
        Array.ForEach(names, Console.Write);
        Console.WriteLine("\n2 by   anonymous   method");
        Array.ForEach(names, delegate(string name) { Console.Write(name+"-"); });
        Console.WriteLine("\n3 by   lamada");
        Array.ForEach(names, name => Console.Write(name+".."));
        Console.WriteLine("\n4 by action 1");
        Array.ForEach(names, new Action<string>(Console.Write)); 
        Console.WriteLine("\n5 by action 2");
        Array.ForEach(names, new Action<string>(delegate(string name) { Console.Write(name + "**"); })); 

datagridview 序号列

'数据绑定
Private Sub BindData()
    Dim bll As New WireBLL.Product
    Dim dt As DataTable = bll.GetList(Me.capacity, currentPage)
    Dim column As New DataColumn
    column.ColumnName = "AutoId"
    column.AutoIncrement = True
    column.AutoIncrementSeed = (Me.currentPage - 1) * Me.capacity + 1
    column.AutoIncrementStep = 1
    Dim dtCol As New DataTable
    dtCol.Columns.Add(column)
    dtCol.Merge(dt)
    Me.DataGridView1.DataSource = dtCol
    If Me.DataGridView1.CurrentRow IsNot Nothing Then
        Me.DataGridView1.CurrentRow.Selected = False
    End If
End Sub

校验相关

private void button1_Click(object sender, EventArgs e)
{
    vali(this.textBox1, string.IsNullOrEmpty);                      //""判断为空
    vali(this.textBox2, IsZero);                                    //00判断为空    
    vali(this.textBox3, str => str == "0.000");                     //0.000判断为空
    vali(this.textBox4, delegate(string  str) { return str == "0"; });//0判断为空
}

private bool IsZero(string str)
{
    return str == "00";
}

private void vali(Control con, Predicate<string> pre)
{
    if (pre(con.Text))
    {
        MessageBox.Show(string.Format("{0} cann't be empty", con.Name));
    }
}