brian0031的专栏

<br />DataTable 加载表结构<br /><br />DataTable dt1 = new DataTable();<br />private void Form1_Load(object sender, EventArgs e)<br />{<br />    dt1.Columns.Add("物料编号", typeof(string));<br />    dt1.Columns.Add("物料名称", typeof(string));<br />    dt1.Columns.Add("

<br />Shift + Tab组合键<br />( 和 Tabindex 有关, 二者的数字相关, 如果textbox1 的 tabindex 为1, 那textbox2就应为2 )<br /> <br />代码一:<br />private void textBox1_KeyUp(object sender, KeyEventArgs e)<br />{<br />    if ((e.KeyCode==Keys.Shift && e.KeyCode==Keys.Tab)==false)<br /> 

<br />提高C#编程水平的50个要点<br /><br />1.总是用属性 (Property) 来代替可访问的数据成员<br />2.在 readonly 和 const 之间，优先使用 readonly<br />3.在 as 和 强制类型转换之间，优先使用 as 操作符<br />4.使用条件属性 (Conditional Attributes) 来代替条件编译语句 #if<br />5.总是为自定义类重载 ToString 方法<br />6.区别值类型和引用类型<br />7.使用不可变的值类

按 tab 键从 textbox1 移到 textbox2private void textBox2_KeyUp(object sender, KeyEventArgs e){    if (e.KeyCode == Keys.Tab)    {        listBox1.Visible = false;    }}

<br />利用正则表达式验证汉字和英文,阿拉伯数字<br /> <br />System.Text.RegularExpressions.Regex reg = new System.Text.RegularExpressions.Regex("^[/u4e00-/u9fa5]+$ || ^[a-zA-Z0-9]+$"); //验证汉字和英文,阿拉伯数字<br />if (reg.Match(textBox5.Text.ToString()).Success)<br />{<br />    //遍历Ar

<br /> <br />private void button1_Click(object sender, EventArgs e)<br />{<br />    string strsql = "SELECT id,name FROM [DepartmentData] group by id,name ";<br />    SqlConnectionStringBuilder CSB = new SqlConnectionStringBuilder();<br />    CSB.DataSourc

<br />using System.Drawing.Printing;<br />Double  myZoom = 1.0;<br /> <br />private void toolStripButton5_Click(object sender, EventArgs e)//放大<br />{<br />    myZoom += 0.1;<br />    printPreviewControl1.Zoom = myZoom;<br />}<br /> <br />private void tool

<br /><br />1.右移代替除法运算、预计算;<br />2.减少冗余计算;<br />3.对于字段和属性，字段访问的速度要快于属性;<br />4.尽量用foreach代替for循环，我记得在哪里看到过，foreach的运行花费时间是for的1/3，有待考证;<br />5.还有就是循环体里面尽量不要写判断语句，因为会影响效率，毕竟你循环一次，程序就做一次判断，这样就有N次循环N次判断，效率大打折扣;<br />6.对于不用改变的“变量”，记得用常量声明;<br />7.string ax=str

C#中字符串赋值,判断空字符串 string str = string.Empty;最好的方法if (str.Length == 0)好的方法:if (str = string.Empty)坏的方法if (string str = "")

DataRow中进行筛选 DataRow[] dr2 = dt.Select("开始日 is not null");for (int k = 0; k {    if ((Convert.ToInt32(dr2[k]["停留时间(H)"].ToString()) > 24) && (Convert.ToInt32(dr2[k]["停留时间(H)"].ToString())

二维数组变一维数组string strsql = string.Format("SELECT top 5 [OldId],RTRIM(LTRIM(ISNULL(Name,) + +ISNULL(Specification,))) as name FROM [MaterialData] where oldid like %{0}% or name like %{1}% "

private void button1_Click(object sender, EventArgs e){    Byte b = 100;    b += 100;  //或者写成 b = (Byte)(b + 100), 但不能写成 b = b + 100;    MessageBox.Show(""+b);//显示200}

private void button1_Click(object sender, EventArgs e){    foreach (Control c in this.Controls)    {        Control c1 = c as Button; //使用了显示转换(强制转换)        if (c1 != null)            c1

 锁定dataGridView左边的列，使锁定的列不随水平滚动条滚动方法一:dataGridView1.Columns[0].Frozen = true;  //只锁定第0列dataGridView1.AllowUserToOrderColumns = true; //更改栏位顺序 方法二:1.dataGridView的contextMenuStrip属性设定为

//自定义类,设定为public,方便但不安全,被他人引用而造成异常(方法1/3)class User{    public string name;  //设定为public,方便但不安全,被他人引用而造成异常    public string sex;    public void SetSex(string values)    {        if (va

private void textBox7_KeyPress(object sender, KeyPressEventArgs e)//需求数量栏位，只能输入数字，并且可以输入小数{    if (e.KeyChar != 13 && e.KeyChar != 8 && !char.IsDigit(e.KeyChar) && e.KeyChar != 46)   e.Handled =

private void button1_Click(object sender, EventArgs e){    int a = 5;    long b = 70000000000;    try    {        checked        {            a = b as int // 也可以写成 a = (int)b;    

class Fruit { }class Apple : Fruit{    public int i = 1;}private void button1_Click(object sender, EventArgs e){    Fruit f = new Apple();    Apple a = f as Apple //也可以写成 Apple a = (

textbox只能输入数字 方法一：private void textBox7_KeyPress(object sender, KeyPressEventArgs e)//只能输入数字和.{    byte[] array = System.Text.Encoding.Default.GetBytes(e.KeyChar.ToString());    if (!cha

dataGridView的计算问题(相乘) private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e){    //总数量=每串数量*串数

DataTable dt_add = new DataTable();DataTable dt_copy = new DataTable();DataSet ds_add = new DataSet();dt_add = (DataTable)dataGrid

SqlCommandBuilder 删除与更新的用法,附代码, 与 dataGridView 结合using System.Data.SqlClient;private void toolStripButton2_Click(object sender, EventArgs e) //保存{    if (dataGridView1.Rows.Count == 0) return;        

•  keycode     8 = BackSpace BackSpace•  keycode     9 = Tab Tab•  keycode    12 = Clear•  keycode    13 = Enter•  keycode    16 = Shift_L•

bool b = false;private void button2_Click(object sender, EventArgs e){    if (b)    {        this.TopMost = true;        b = false;    }

A,a  字母与数字&  键盘可输入字符#  数字"0-9",空格,"+-"9  数字"0-9",空格0  数字"0-9"

DataTable dtb2 = new DataTable();string[] m_list = new string[dtb2.Rows.Count];for (int i = 0; i {    m_list[i] = dtb2.Rows[i][0].

DataTable dtsve = new DataTable();private void toolStripButton6_Click(object sender, EventArgs e) //保存{    if (dataGridView1.Rows.Count > 0)

using System.Drawing.Printing;PrintDocument pdc = new PrintDocument();private void form2_Load(object sender, EventArgs e){    printPreviewCo

方法一:using System.Drawing.Printing;using System.Drawing.Drawing2D;private void toolStripButton7_Click(object sender, EventArgs e) //列印{    Pr

using System.Drawing.Printing;using System.Drawing.Drawing2D; //每隔55个字换行int k = Ds.Tables[0].Rows[0]["请购原因"].ToString().Trim().Length / 55;i

int b = 0;int c = 0;int d = 0;private void form2_Load(object sender, EventArgs e){    foreach (PaperSize ps5 in pdc.PrinterSettings.PaperSiz

方法一:private void toolStripButton7_Click(object sender, EventArgs e){    PrintDialog pDlg = new PrintDialog();    pDlg.AllowSomePages = true;

private int page;private int maxpage;private int b = 0;  //导入相关数据时用到，第几笔资料private int c = 0;  //显示共多少页  private void form2_Load(object sende

private void dataGridView1_KeyDown(object sender, KeyEventArgs e) //按下回车执行tab{    if (this.dataGridView1.Focused && e.KeyCode == Keys.Enter)

DataGridViewCheckBoxColumn dtchk = new DataGridViewCheckBoxColumn();dtchk.DataPropertyName = "chk";dtchk.HeaderText = "";dataGridView1.Colum

private void copyToolStripMenuItem_Click(object sender, EventArgs e) //复制{    if (this.dataGridView1.GetCellCount(DataGridViewElementStates.

private void all_ToolStripMenuItem_Click(object sender, EventArgs e){    this.textBox1.Focus();    for (int i = 0; i     {        this.dataG

public DataGridViewTextBoxEditingControl CellEdit = null;private void dataGridView1_EditingControlShowing(object sender, DataGridV

private void reversed_ToolStripMenuItem_Click(object sender, EventArgs e){    foreach ( DataGridViewRow drw in this.dataGridView1.Rows)    {

datagridview新增行，在有栏位的情况下DataRow dr = ((DataTable)dataGridView1.DataSource).NewRow();((DataTable)dataGridView1.DataSource).Rows.Add(dr); data