C # (winform) Example of operating the .txt text

 

Background: A textbox can be input to implement the search function.

Function Improvement requirement: the textbox is transformed into an input drop-down box. The content of the drop-down box is a historical search record (the content of the last 20 input searches)

Www.2cto.com

Code:

 

Using System. IO;

Using System. Text. RegularExpressions;

 

Private ArrayList _ arrSearchHistory = null; // The global variable form_loadreads the content in the. TXT text.

 

// Put it in form_load

ReadTxtFile (out _ arrSearchHistory );

If (_ arrSearchHistory! = Null & _ arrSearchHistory. Count> 0)

{

SetComboList (cboFilter, _ arrSearchHistory, null, "", false, true );

}

 

// Added to the search function

If (! String. IsNullOrEmpty (cboFilter. Text) & cboFilter. Text. Trim (). Length> 1)

{

AddItemToTxt (System. windows. forms. application. startupPath. replace (@ "bin \ Debug", "") + "/Data/SearchHistory.txt", cboFilter. text, out _ arrSearchHistory );

}

 

// Public Functions

Private void ReadTxtFile (out ArrayList arrFile, int iTopRow = 20)

{

ArrFile = new ArrayList ();

Try

{

String sFileFullName = System. Windows. Forms. Application. StartupPath. Replace (@ "bin \ Debug", "") + @ "/Data ";

If (! System. IO. Directory. Exists (sFileFullName ))

{

System. IO. Directory. CreateDirectory (sFileFullName );

}

 

SFileFullName + = @ "/SearchHistory.txt ";

If (! System. IO. File. Exists (sFileFullName ))

{

// System. IO. File. CreateText (sFileName );

FileStream fs;

Fs = File. Create (sFileFullName );

Fs. Close ();

}

 

FileStream fsTxtFile = new FileStream (sFileFullName, FileMode. Open, FileAccess. Read );

StreamReader sr = new StreamReader (fsTxtFile, System. Text. Encoding. Default );

String sTemp;

 

STemp = sr. ReadLine ();

Int iTempRow = 0;

While (! String. IsNullOrEmpty (sTemp ))

{

ITempRow ++;

If (iTempRow> iTopRow)

{

Break;

}

ArrFile. Add (sTemp );

STemp = sr. ReadLine ();

}

 

Sr. Close ();

Sr. Dispose ();

FsTxtFile. Dispose ();

}

Catch (Exception ex)

{

Common. DisplayMsg (this. Text, ex. Message. ToString ());

}

}

 

/// <Summary>

/// Calculate the number of times a substring appears.

/// </Summary>

/// <Param name = "str"> string </param>

/// <Param name = "substring"> substring </param>

/// <Returns> Number of occurrences </returns>

Public static int SubstringCount (string str, string substring)

{

If (str. Contains (substring ))

{

String strReplaced = str. Replace (substring ,"");

Return (str. Length-strReplaced. Length)/substring. Length;

}

 

Return 0;

}

 

Private void AddItemToTxt (string sFileFullName, string sNewItem, out ArrayList arrFile)

{

ArrFile = _ arrSearchHistory;

 

Try

{

String sTemp = "";

Using (StreamReader sr = new StreamReader (sFileFullName ))

{

Sr. BaseStream. Flush ();

STemp = sr. ReadToEnd ();

 

Int iCount = SubstringCount (sTemp, "\ r \ n ");

If (iCount> 20)

{

Regex reg = new Regex ("\ r \ n ");

Match mat = reg. Match (sTemp );

Int iCountTemp = 0;

While (mat. Success)

{

ICountTemp ++;

// MessageBox. Show (mat. Index. ToString (); // location

If (iCountTemp> 20)

{

STemp = sTemp. Substring (0, mat. Index );

Break;

}

Mat = reg. Match (sTemp, mat. Index + mat. Length );

}

}

}

 

// If (File. Exists (sFileFullName ))

//{

// File. Delete (sFileFullName );

//}

 

FileStream fsTxtWrite = new FileStream (sFileFullName, FileMode. Create, FileAccess. Write );

StreamWriter srWrite = new StreamWriter (fsTxtWrite, System. Text. Encoding. UTF8 );

// StreamWriter srWrite = new StreamWriter (fsTxtWrite, System. Text. Encoding. Default );

If (! STemp. Contains (sNewItem ))

{

ArrFile. Insert (0, sNewItem );

SrWrite. WriteLine (sNewItem );

SrWrite. Write (sTemp );

}

Else

{

SrWrite. Write (sTemp );

}

 

SrWrite. Close ();

SrWrite. Dispose ();

FsTxtWrite. Dispose ();

}

Catch (Exception ex)

{

Common. DisplayMsg (this. Text, ex. Message. ToString ());

}

}

 

// Set parameters in the drop-down box (the drop-down box control to be set, the query statement, the content of the first line by default)

Public static void SetComboList (DevExpress. XtraEditors. ComboBoxEdit ComboList, ArrayList arrSource = null, DataTable dtSource = null, string FirstRowText = "", bool bSelectFirstItem = false, bool bEditable = false)

{

DataTable dtList = null;

If (dtSource! = Null)

{

DtList = dtSource;

}

Else if (arrSource! = Null)

{

DtList = new DataTable ();

DtList. Columns. Add ("name ");

Foreach (string s in arrSource)

{

DtList. Rows. Add (s );

}

}

Else {return ;}

 

Int intCount = (dtList! = Null )? DtList. Rows. Count: 0;

If (bEditable)

{

ComboList. Properties. TextEditStyle = TextEditStyles. Standard;

}

Else

{

ComboList. Properties. TextEditStyle = TextEditStyles. DisableTextEditor; // You Cannot edit the comboBox text value.

}

ComboList. Properties. Items. Clear ();

If (! String. IsNullOrEmpty (FirstRowText) ComboList. Properties. Items. Add (FirstRowText );

 

If (intCount> 0)

{

For (int I = 0; I <intCount; I ++)

{

ComboList. Properties. Items. Add (dtList. Rows [I] [0]. ToString ());

}

}

If (bSelectFirstItem) ComboList. SelectedIndex = 0; // you can specify 1st items.

}

 

Public static void DisplayMsg (string sCaption, string sMsg)

{

XtraMessageBox. Show (sMsg, sCaption );

}

Hope to help people in need.

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