Solved

charp variable

Posted on 2009-05-18
1
236 Views
Last Modified: 2012-05-07
private void listBox1_DragOver(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }



why we no need to declare  Type of  e.Effect      such as object e.Effect    or int  e.Effect

I am very new for csharp
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
 
using System.Data.SqlClient;
 
namespace CDLib
{
    public partial class CDEntry : Form
    {
        public CDEntry()
        {
            InitializeComponent();
        }
 
        private void label3_Click(object sender, EventArgs e)
        {
 
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
 
        }
 
        private void listBox1_DragOver(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }
 
        private void listBox1_DragDrop(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                // Reads the Drop files int to a string array;
                string[] filePaths =
                    (string[])(e.Data.GetData(DataFormats.FileDrop));
 
                // Iteraction 
                foreach (string filename in filePaths)
                {
                    string keyword = Path.GetFileNameWithoutExtension(filename);
                    this.AddKeyWord(keyword);
                }
            }
 
        }
 
        int AddKeyWord(string keyword)
        {
            string lowercaseKeyword = keyword.ToLower();
 
            int idx = KeyWordList.Items.IndexOf(lowercaseKeyword);
            if (idx == -1)
            {
                KeyWordList.Items.Add(lowercaseKeyword);
 
            }
 
            return idx;
        }
 
        private void SaveButton_Click(object sender, EventArgs e)
        {
            // Validate Form fields
 
            if (tbCdName.Text.Length < 5)
            {
                MessageBox.Show("Please enter a valid CD Name (min. 5 Characters)");
                return;
 
            }
 
            if (KeyWordList.Items.Count < 1)
            {
                MessageBox.Show("Please add Key Words to the keyword List");
                return;
            }
 
            try
            {
                this.Opacity = 40.0;
                this.Enabled = false;
                this.Cursor = Cursors.WaitCursor;
 
                if (SaveData())
                {
                    MessageBox.Show("CD Entry saved succesfully!");
                    this.Close();
                }
            }
            finally
            {
                this.Opacity = 100.0;
                this.Enabled = true;
                this.Cursor = Cursors.Default;
            }
 
          
        }
 
 
        
        /// <summary>
        /// Store the CD Entry to the Database
        /// </summary>
        /// <returns></returns>
        bool SaveData()
        {
            bool result = false;
 
            int cdLibraryID = 0;
 
            //TODO: Use a transaction in this scope
            // Create a connection 
            using (SqlConnection conn = new SqlConnection(CDLib.Program.Connstring))
            {
                // Create SqlCommand. We use a T-SQL Store Procedure
                // to insert the Data in to the CdLibrary table
                using (SqlCommand cmd = new SqlCommand("insert_CdLibrary", conn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
 
                    cmd.Parameters.AddWithValue("@CdName", tbCdName.Text);
                    cmd.Parameters.AddWithValue("@CdDescription", tbCdDescription.Text);
                    cmd.Parameters.AddWithValue("@Location", tbCdLocation.Text);
                    cmd.Parameters.AddWithValue("@CdType", "");
 
 
                    try
                    {
                        conn.Open();
                        cdLibraryID = Convert.ToInt32(cmd.ExecuteScalar());
                    }
                    catch (Exception ex)
                    {
                        conn.Close();
                        MessageBox.Show(ex.Message);
                        return false;
                    }
                    
                }
                // Create SqlCommand. We use a T-SQL Store Procedure
                // to insert the Data in to the CdLibrary_keyword table
                using (SqlCommand cmd = new SqlCommand("insert_cdkeywords", conn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
 
                    cmd.Parameters.AddWithValue("@EntryCDID", cdLibraryID);
                    cmd.Parameters.AddWithValue("@KeyWordIDList", GetKeyWordList());
 
 
 
                    try
                    {
                        cmd.ExecuteScalar();
                    }
                    catch (Exception ex)
                    {
                        conn.Close();
                        MessageBox.Show(ex.Message);
                        return false;
                    }
 
 
                    result = true;
                }
            }
 
 
            return result;
        }
 
        private string GetKeyWordList()
        {
            string result = string.Empty;
 
            for (int i = 0; i < KeyWordList.Items.Count - 1; i++ )
            {
                result += KeyWordList.Items[i].ToString() + ';';
            }
 
            return result;
            
        }
 
        private void CancelButton_Click(object sender, EventArgs e)
        {
            this.Close();
        }
 
        private void AddKeyWordButton_Click(object sender, EventArgs e)
        {
 
            if(tbKeyWord.Text.Length < 5)
            {
                MessageBox.Show("Please enter a valid KeyWord (min. 5 Characters)");
                return;
 
            }
 
            if (AddKeyWord(tbKeyWord.Text) != -1)
            {
                MessageBox.Show(string.Format("Keyword :{0} allready exists! Please try again.", tbKeyWord.Text));
                return;
            }
 
        }
 
        private void KeyWordList_SelectedIndexChanged(object sender, EventArgs e)
        {
            int idx = KeyWordList.SelectedIndex;
            if (idx != -1)
            {
                tbKeyWord.Text = KeyWordList.Items[idx].ToString();
            }
        }
 
       
 
        private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
        {
            if (KeyWordList.SelectedIndex == -1)
                e.Cancel = true;
 
        }
 
        private void deleteToolStripMenuItem_Click(object sender, EventArgs e)
        {
             int idx = KeyWordList.SelectedIndex;
 
             if (idx != -1)
             {
                 DialogResult result =
                     MessageBox.Show("Are you sure you want to delete this item?", "", 
                     MessageBoxButtons.YesNo, MessageBoxIcon.Question);
                 if(result == DialogResult.Yes)
                     KeyWordList.Items.RemoveAt(idx);
 
             }
        }
 
       
    }
}

Open in new window

0
Comment
Question by:teera
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 10

Accepted Solution

by:
oxyoo earned 500 total points
ID: 24418714
Hi
The variable "e" is already declared as an DragEventArgs in the method as a parameter (DragEventArgs e) this means that you can use the variable e anywhere inside the listBox1_DragDrop method.
0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Extention Methods in C# 3.0 by Ivo Stoykov C# 3.0 offers extension methods. They allow extending existing classes without changing the class's source code or relying on inheritance. These are static methods invoked as instance method. This…
Article by: Ivo
C# And Nullable Types Since 2.0 C# has Nullable(T) Generic Structure. The idea behind is to allow value type objects to have null values just like reference types have. This concerns scenarios where not all data sources have values (like a databa…
This video Micro Tutorial shows how to password-protect PDF files with free software. Many software products can do this, such as Adobe Acrobat (but not Adobe Reader), Nuance PaperPort, and Nuance Power PDF, but they are not free products. This vide…
There's a multitude of different network monitoring solutions out there, and you're probably wondering what makes NetCrunch so special. It's completely agentless, but does let you create an agent, if you desire. It offers powerful scalability …

705 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question