• 所有问题

    • C#一道题 请高手指点

    using System;
    using System.Drawing;
    using System.Collections;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Data;
    using System.IO;
    using System.Text;

    namespace Edit
    {
    public class Form1 : System.Windows.Forms.Form
    {
    private System.Windows.Forms.Label lblFileName;
    private System.Windows.Forms.TextBox txtFileName;
    private System.Windows.Forms.TextBox txtContent;
    private System.Windows.Forms.Button btnSave;
    private System.ComponentModel.Container components = null;

    public Form1()
    {
    InitializeComponent();
    }
    protected override void Dispose( bool disposing )
    {
    if( disposing )
    {
    if (components != null)
    {
    components.Dispose();
    }
    }
    base.Dispose( disposing );
    }
    [STAThread]
    static void Main()
    {
    Application.Run(new Form1());
    }

    private void btnSave_Click(object sender, System.EventArgs e)
    {
    FileStream fs;
    try
    {
    fs=File.Create(txtFileName.Text);
    }
    catch
    {
    MessageBox.Show("建立文件时出错。","错误",
    System.Windows.Forms.MessageBoxButtons.OK,
    System.Windows.Forms.MessageBoxIcon.Warning);
    }
    byte[] content=new
    UTF8Encoding(true).GetBytes(txtContent.Text);
    try
    {
    fs.Write(content,0,content.Length);
    fs.Flush();
    MessageBox.Show("保存成功","保存",
    System.Windows.Forms.MessageBoxButtons.OK,
    System.Windows.Forms.MessageBoxIcon.Information);
    }
    catch
    {
    MessageBox.Show("写入文件时出错。","错误",
    System.Windows.Forms.MessageBoxButtons.OK,
    System.Windows.Forms.MessageBoxIcon.Warning);
    }
    finally
    {
    fs.Close();
    }
    }
    }
    }
    提示说使用了为赋值的局部变量 我应该怎么改呢

    举报该问题
    推荐答案   2007-01-10
    下面是一个实例.你仔细看看.不清楚在照我.QQ 568721697
    using System;
    using System.Data;
    using System.Data.SqlClient;
    using System.Drawing;
    using System.Collections;
    using System.ComponentModel;
    using System.Windows.Forms;
    using tables

    namespace 企业人事管理系统
    {
    /// <summary>
    /// FrmLogin 的摘要说明。
    /// </summary>
    public class FrmLogin : System.Windows.Forms.Form
    {
    private System.Windows.Forms.PictureBox pictureBox1;
    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.Button button2;
    private System.Windows.Forms.TextBox textBox1;
    private System.Windows.Forms.TextBox textBox2;
    private System.Windows.Forms.Label label1;
    private System.Windows.Forms.Label label2;

    private string UserName;
    private string PassWord;

    private string sql;
    private System.Data.OleDb.OleDbDataAdapter oleDbDataAdapter1;
    private System.Data.OleDb.OleDbCommand oleDbSelectCommand1;
    private System.Data.OleDb.OleDbCommand oleDbInsertCommand1;
    private System.Data.OleDb.OleDbCommand oleDbUpdateCommand1;
    private System.Data.OleDb.OleDbCommand oleDbDeleteCommand1;
    private System.Data.OleDb.OleDbConnection oleDbConnection1;
    private 企业人事管理系统.DataSet2 dataSet21;
    private System.Windows.Forms.DataGrid dataGrid1;

    /// <summary>
    /// 必需的设计器变量。
    /// </summary>

    private System.ComponentModel.Container components = null;

    public FrmLogin()
    {
    //
    // Windows 窗体设计器支持所必需的
    //

    InitializeComponent();

    //
    // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
    //
    }

    /// <summary>
    /// 清理所有正在使用的资源。
    /// </summary>
    protected override void Dispose( bool disposing )
    {
    if( disposing )
    {
    if(components != null)
    {
    components.Dispose();
    }
    }
    base.Dispose( disposing );
    }

    #region Windows 窗体设计器生成的代码
    /// <summary>
    /// 设计器支持所需的方法 - 不要使用代码编辑器修改
    /// 此方法的内容。
    /// </summary>
    private void InitializeComponent()
    {
    this.pictureBox1 = new System.Windows.Forms.PictureBox();
    this.button1 = new System.Windows.Forms.Button();
    this.button2 = new System.Windows.Forms.Button();
    this.textBox1 = new System.Windows.Forms.TextBox();
    this.textBox2 = new System.Windows.Forms.TextBox();
    this.label1 = new System.Windows.Forms.Label();
    this.label2 = new System.Windows.Forms.Label();
    this.oleDbDataAdapter1 = new System.Data.OleDb.OleDbDataAdapter();
    this.oleDbDeleteCommand1 = new System.Data.OleDb.OleDbCommand();
    this.oleDbConnection1 = new System.Data.OleDb.OleDbConnection();
    this.oleDbInsertCommand1 = new System.Data.OleDb.OleDbCommand();
    this.oleDbSelectCommand1 = new System.Data.OleDb.OleDbCommand();
    this.oleDbUpdateCommand1 = new System.Data.OleDb.OleDbCommand();
    this.dataSet21 = new 企业人事管理系统.DataSet2();
    this.dataGrid1 = new System.Windows.Forms.DataGrid();
    ((System.ComponentModel.ISupportInitialize)(this.dataSet21)).BeginInit();
    ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
    this.SuspendLayout();
    //
    // pictureBox1
    //
    this.pictureBox1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
    this.pictureBox1.Location = new System.Drawing.Point(40, 32);
    this.pictureBox1.Name = "pictureBox1";
    this.pictureBox1.Size = new System.Drawing.Size(272, 96);
    this.pictureBox1.TabIndex = 0;
    this.pictureBox1.TabStop = false;
    //
    // button1
    //
    this.button1.Location = new System.Drawing.Point(72, 152);
    this.button1.Name = "button1";
    this.button1.TabIndex = 1;
    this.button1.Text = "登录";
    this.button1.Click += new System.EventHandler(this.button1_Click);
    //
    // button2
    //
    this.button2.Location = new System.Drawing.Point(200, 152);
    this.button2.Name = "button2";
    this.button2.TabIndex = 2;
    this.button2.Text = "取消";
    this.button2.Click += new System.EventHandler(this.button2_Click);
    //
    // textBox1
    //
    this.textBox1.Location = new System.Drawing.Point(144, 56);
    this.textBox1.Name = "textBox1";
    this.textBox1.Size = new System.Drawing.Size(128, 21);
    this.textBox1.TabIndex = 3;
    this.textBox1.Text = "";
    this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
    //
    // textBox2
    //
    this.textBox2.Location = new System.Drawing.Point(144, 96);
    this.textBox2.Name = "textBox2";
    this.textBox2.Size = new System.Drawing.Size(128, 21);
    this.textBox2.TabIndex = 4;
    this.textBox2.Text = "";
    //
    // label1
    //
    this.label1.Location = new System.Drawing.Point(56, 56);
    this.label1.Name = "label1";
    this.label1.Size = new System.Drawing.Size(88, 23);
    this.label1.TabIndex = 5;
    this.label1.Text = "***名称";
    //
    // label2
    //
    this.label2.Location = new System.Drawing.Point(56, 96);
    this.label2.Name = "label2";
    this.label2.Size = new System.Drawing.Size(88, 23);
    this.label2.TabIndex = 6;
    this.label2.Text = "***口令";
    //
    // oleDbDataAdapter1
    //
    this.oleDbDataAdapter1.DeleteCommand = this.oleDbDeleteCommand1;
    this.oleDbDataAdapter1.InsertCommand = this.oleDbInsertCommand1;
    this.oleDbDataAdapter1.SelectCommand = this.oleDbSelectCommand1;
    this.oleDbDataAdapter1.TableMappings.AddRange(new System.Data.Common.DataTableMapping[] {
    new System.Data.Common.DataTableMapping("Table", "管理用户", new System.Data.Common.DataColumnMapping[] {
    new System.Data.Common.DataColumnMapping("用户口令", "用户口令"),
    new System.Data.Common.DataColumnMapping("用户名称", "用户名称"),
    new System.Data.Common.DataColumnMapping("用户权限", "用户权限")})});
    this.oleDbDataAdapter1.UpdateCommand = this.oleDbUpdateCommand1;
    //
    // oleDbDeleteCommand1
    //
    this.oleDbDeleteCommand1.CommandText = "DELETE FROM 管理用户 WHERE (用户名称 = ?) AND (用户口令 = ? OR ? IS NULL AND 用户口令 IS NULL) AN" +
    "D (用户权限 = ? OR ? IS NULL AND 用户权限 IS NULL)";
    this.oleDbDeleteCommand1.Connection = this.oleDbConnection1;
    this.oleDbDeleteCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户名称", System.Data.OleDb.OleDbType.VarWChar, 15, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户名称", System.Data.DataRowVersion.Original, null));
    this.oleDbDeleteCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户口令", System.Data.OleDb.OleDbType.VarWChar, 10, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户口令", System.Data.DataRowVersion.Original, null));
    this.oleDbDeleteCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户口令1", System.Data.OleDb.OleDbType.VarWChar, 10, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户口令", System.Data.DataRowVersion.Original, null));
    this.oleDbDeleteCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户权限", System.Data.OleDb.OleDbType.VarWChar, 15, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户权限", System.Data.DataRowVersion.Original, null));
    this.oleDbDeleteCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户权限1", System.Data.OleDb.OleDbType.VarWChar, 15, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户权限", System.Data.DataRowVersion.Original, null));
    //
    // oleDbConnection1
    //
    this.oleDbConnection1.ConnectionString = @"Jet OLEDB:Global Partial Bulk Ops=2;Jet OLEDB:Registry Path=;Jet OLEDB:Database Locking Mode=1;Jet OLEDB:Database Password=;Data Source=""g:/document. and Settings/Administrator/My document./Visual Studio Projects/企业人事管理系统/企业人事管理系统/DateBase/DateBase.mdb"";Password=;Jet OLEDB:Engine Type=5;Jet OLEDB:Global Bulk Transactions=1;Provider=""Microsoft.Jet.OLEDB.4.0"";Jet OLEDB:System database=;Jet OLEDB:SFP=False;Extended Properties=;Mode=Share Deny None;Jet OLEDB:New Database Password=;Jet OLEDB:Create System Database=False;Jet OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repair=False;User ID=Admin;Jet OLEDB:Encrypt Database=False";
    //
    // oleDbInsertCommand1
    //
    this.oleDbInsertCommand1.CommandText = "INSERT INTO 管理用户(用户口令, 用户名称, 用户权限) valueS (?, ?, ?)";
    this.oleDbInsertCommand1.Connection = this.oleDbConnection1;
    this.oleDbInsertCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("用户口令", System.Data.OleDb.OleDbType.VarWChar, 10, "用户口令"));
    this.oleDbInsertCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("用户名称", System.Data.OleDb.OleDbType.VarWChar, 15, "用户名称"));
    this.oleDbInsertCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("用户权限", System.Data.OleDb.OleDbType.VarWChar, 15, "用户权限"));
    //
    // oleDbSelectCommand1
    //
    this.oleDbSelectCommand1.CommandText = "SELECT 用户口令, 用户名称, 用户权限 FROM 管理用户";
    this.oleDbSelectCommand1.Connection = this.oleDbConnection1;
    //
    // oleDbUpdateCommand1
    //
    this.oleDbUpdateCommand1.CommandText = "UPDATE 管理用户 SET 用户口令 = ?, 用户名称 = ?, 用户权限 = ? WHERE (用户名称 = ?) AND (用户口令 = ? OR ? " +
    "IS NULL AND 用户口令 IS NULL) AND (用户权限 = ? OR ? IS NULL AND 用户权限 IS NULL)";
    this.oleDbUpdateCommand1.Connection = this.oleDbConnection1;
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("用户口令", System.Data.OleDb.OleDbType.VarWChar, 10, "用户口令"));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("用户名称", System.Data.OleDb.OleDbType.VarWChar, 15, "用户名称"));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("用户权限", System.Data.OleDb.OleDbType.VarWChar, 15, "用户权限"));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户名称", System.Data.OleDb.OleDbType.VarWChar, 15, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户名称", System.Data.DataRowVersion.Original, null));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户口令", System.Data.OleDb.OleDbType.VarWChar, 10, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户口令", System.Data.DataRowVersion.Original, null));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户口令1", System.Data.OleDb.OleDbType.VarWChar, 10, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户口令", System.Data.DataRowVersion.Original, null));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户权限", System.Data.OleDb.OleDbType.VarWChar, 15, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户权限", System.Data.DataRowVersion.Original, null));
    this.oleDbUpdateCommand1.Parameters.Add(new System.Data.OleDb.OleDbParameter("Original_用户权限1", System.Data.OleDb.OleDbType.VarWChar, 15, System.Data.ParameterDirection.Input, false, ((System.Byte)(0)), ((System.Byte)(0)), "用户权限", System.Data.DataRowVersion.Original, null));
    //
    // dataSet21
    //
    this.dataSet21.DataSetName = "DataSet2";
    this.dataSet21.Locale = new System.Globalization.CultureInfo("zh-CN");
    //
    // dataGrid1
    //
    this.dataGrid1.AlternatingBackColor = System.Drawing.Color.GhostWhite;
    this.dataGrid1.BackColor = System.Drawing.Color.GhostWhite;
    this.dataGrid1.BackgroundColor = System.Drawing.Color.Lavender;
    this.dataGrid1.BorderStyle = System.Windows.Forms.BorderStyle.None;
    this.dataGrid1.CaptionBackColor = System.Drawing.Color.RoyalBlue;
    this.dataGrid1.CaptionForeColor = System.Drawing.Color.White;
    this.dataGrid1.DataMember = "";
    this.dataGrid1.DataSource = this.dataSet21.管理用户;
    this.dataGrid1.FlatMode = true;
    this.dataGrid1.Font = new System.Drawing.Font("Tahoma", 8F);
    this.dataGrid1.ForeColor = System.Drawing.Color.MidnightBlue;
    this.dataGrid1.GridLineColor = System.Drawing.Color.RoyalBlue;
    this.dataGrid1.HeaderBackColor = System.Drawing.Color.MidnightBlue;
    this.dataGrid1.HeaderFont = new System.Drawing.Font("Tahoma", 8F, System.Drawing.FontStyle.Bold);
    this.dataGrid1.HeaderForeColor = System.Drawing.Color.Lavender;
    this.dataGrid1.LinkColor = System.Drawing.Color.Teal;
    this.dataGrid1.Location = new System.Drawing.Point(8, 192);
    this.dataGrid1.Name = "dataGrid1";
    this.dataGrid1.ParentRowsBackColor = System.Drawing.Color.Lavender;
    this.dataGrid1.ParentRowsForeColor = System.Drawing.Color.MidnightBlue;
    this.dataGrid1.SelectionBackColor = System.Drawing.Color.Teal;
    this.dataGrid1.SelectionForeColor = System.Drawing.Color.PaleGreen;
    this.dataGrid1.Size = new System.Drawing.Size(328, 152);
    this.dataGrid1.TabIndex = 7;
    //
    // FrmLogin
    //
    this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
    this.ClientSize = new System.Drawing.Size(352, 352);
    this.Controls.Add(this.dataGrid1);
    this.Controls.Add(this.label2);
    this.Controls.Add(this.label1);
    this.Controls.Add(this.textBox2);
    this.Controls.Add(this.textBox1);
    this.Controls.Add(this.button2);
    this.Controls.Add(this.button1);
    this.Controls.Add(this.pictureBox1);
    this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
    this.Name = "FrmLogin";
    this.StartPosition = System.Windows.Forms.FormStartPosition.CenterParent;
    this.Text = "FrmLogin";
    ((System.ComponentModel.ISupportInitialize)(this.dataSet21)).EndInit();
    ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
    this.ResumeLayout(false);

    }
    #endregion

    private void textBox1_TextChanged(object sender, System.EventArgs e)
    {

    }

    public void FillDataSet(DataSet2 dataSet21)
    {
    //在填充数据集前关闭约束检查
    //这允许适配器填充数据集而不用考虑
    //表之间的依赖项
    dataSet21.EnforceConstraints=false;
    try
    {
    //打开连接
    if(this.oleDbConnection1.State!=ConnectionState.Closed)
    this.oleDbConnection1.Close();
    this.oleDbConnection1.Open();
    //尝试通过 oleDbDataAdapter1 填充数据集
    this.oleDbDataAdapter1.Fill(dataSet21);

    }
    catch(Exception fillException)
    {
    //在此处添加错误处理代理
    MessageBox.Show(fillException.Message);
    }
    finally
    {
    dataSet21.EnforceConstraints=true;
    this.oleDbConnection1.Close();
    }

    }
    public void LoadDataSet()
    {
    //创建一个新数据集以保存从FillDataSet 调用返回的记录.
    //使用了一个临时数据集，这是因为填充现在的数据集
    //需要重新绑定数据绑定
    DataSet2 objDataSetTemp=new DataSet2();
    try
    {
    this.FillDataSet(objDataSetTemp);
    }
    catch(Exception eFillDataSet)
    {
    MessageBox.Show(eFillDataSet.Message);
    }
    try
    {
    this.dataSet21.Clear();
    this.dataSet21.Merge(objDataSetTemp);
    }
    catch(Exception eLoadMerge)
    {
    MessageBox.Show(eLoadMerge.Message);
    }
    }

    private void button1_Click(object sender, System.EventArgs e)
    {
    //用户验证代码
    UserName=this.textBox1.Text.Trim();
    PassWord=this.textBox2.Text.Trim();

    if(UserName!=null&&PassWord!=null)
    {
    sql="SELECT 用户口令, 用户名称, 用户权限 FROM 管理用户 WHERE 用户名称 = '"+ UserName + "' and 用户口令 ='" + PassWord + "'";

    }

    if(UserName!=null&&PassWord!=null)
    {
    this.oleDbSelectCommand1.CommandText=sql;

    参考资料：http://www.chinaddv.com/WebProgram/C/2006/04-24/1145878582660.html

    温馨提示：答案为网友推荐，仅供参考
    其他回答
    第1个回答  2007-01-10
    没看出程序有什么问题，
    你到底想要做什么？
    不过我好像没这么用过，
    我用时一个方法里有一个try,多个catch,一个fianlly（或没有）。
    catch (ArgumentOutOfRangeException e)
    {
    }
    catch (ArgumentNullException e)
    {
    }
    catch (ArgumentException e)
    {
    }
    catch (Exception e)
    {
    }
    可以写捕捉异常的类型，但 Exception 是异常的集合，必须放在最后。
    第2个回答  2007-01-10
    废话，赋一个值就可以了~
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