Question

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

Answer 1

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;

Answer 2

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。

Answer 3

废话，赋一个值就可以了~