How do import excel database in C#?

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C#

MVVM

I have an excel table that contains 3 columns but contains a variable number of rows.
And I want to insert this excel table into rows and columns that are the same as the database table.I would like to import the database by selecting the Excel file.But I wasn't successful.
I'm waiting for your help on this.

My process steps are as follows.

1.Excel selection (Done)
2. Read the selected option. (reads in foreach but does not write)
3. Insert the rows and columns in the same way into the table structure. (Not done)

What I have tried:

//Insert button action method

private void ExcelImport(object obj){
    Excel.Application app=new Excel.Application();
    Excel.Workbook workbook=app.workbooks.Open(fileName,Type.Missing,Type.Missing);
    Excel.Worksheet sheet=workbook.Sheets[1];
    Excel.Range range=sheet.UsedRange;

  
}